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Getting Started

  • Overview
    • Design concept
    • Unified interface
    • File-based architecture
    • Modular workflow design
    • User control
    • Local and HPC workflows
    • Extensibility
    • Scope
  • Features
    • Pre-processing
      • Structure and input preparation
      • Pseudopotentials
      • Brillouin-zone sampling
      • Convergence workflows
      • Reaction pathways and dynamics
    • Post-processing
      • General calculation analysis
      • Structural analysis
      • Electronic structure
      • Charge, localization, and bonding
      • Energetics and thermodynamics
      • AIMD and trajectory analysis
      • Mechanical and structural materials analysis
      • Phonon-derived transport descriptors
    • Application-oriented analysis
    • VASP and Quantum ESPRESSO support
    • Output and visualization
  • Installation
    • Requirements
    • Recommended installation
    • Windows
    • Linux
    • Linux / HPC
    • Verify installation
    • Install from source
    • Development installation
    • Updating VQkit
    • Uninstalling VQkit
    • Troubleshooting
      • Command not found
      • Python version
      • Package information
      • Reinstall if necessary

Tutorials

  • Tutorials
    • Start here
    • Electronic-structure tutorials
    • Charge and bonding tutorials
    • Dynamics and reaction-path tutorials
    • Tutorial index
      • Input Generation
        • Important
        • Open the Pre-processing menu
        • 1. Create a new calculation
        • VASP input generation
        • VASP KPOINTS
        • VASP POSCAR and POTCAR
        • VASP generated directory
        • Quantum ESPRESSO input generation
        • QE directory structure
        • Editing QE starter inputs
        • QE prerequisite stages
        • 2. Convert CIF to input
        • 3. Convert output to input
        • Structure editing
        • Pre-flight input validation
        • Example: VASP SCF starter
        • Example: QE DOS starter
        • Recommended workflow
        • Scientific cautions
      • Band Structure
        • Typical workflow
        • High-symmetry K-path preparation
        • Symmetry path menu
        • Symmetry tolerance
        • K-point density along the path
        • Generated K-path files
        • Band calculation: VASP
        • Band calculation: Quantum ESPRESSO
        • Band-structure analysis
        • Band report
        • Generated outputs
        • VASP example
        • Quantum ESPRESSO example
        • Band-gap analysis
        • Recommended workflow
        • Scientific cautions
      • DOS and PDOS
        • Open the electronic-structure menu
        • DOS workflow
        • Running DOS analysis
        • DOS report
        • Fermi-level reference
        • Spin-polarized DOS
        • DOS outputs
        • Example: VASP DOS
        • Quantum ESPRESSO DOS example
        • PDOS workflow
        • VASP requirements for PDOS
        • Quantum ESPRESSO requirements for PDOS
        • Running PDOS analysis
        • Atom selection
        • Orbital-group selection
        • p-orbital components
        • d-orbital components
        • PDOS report
        • PDOS output naming
        • PDOS data export
        • Spin-polarized PDOS plot
        • Example: VASP atom-resolved d-PDOS
        • Example: Quantum ESPRESSO projected DOS
        • Orbital interpretation
        • Common problems
        • Recommended DOS/PDOS workflow
        • Scientific cautions
      • Work Function
        • Open the work-function workflow
        • VASP workflow
        • Generating LOCPOT
        • Choose the slab-normal axis
        • Planar averaging of LOCPOT
        • Vacuum regions
        • Work-function calculation
        • VASP output report
        • Generated files
        • Work-function plot
        • Vacuum-flatness warning
        • Example: VASP slab
        • Quantum ESPRESSO workflow
        • QE Fermi energy
        • No QE planar profile found
        • QE pp.x input
        • QE saved data
        • QE average.x input
        • Automatic QE execution
        • Manual QE execution
        • QE unit handling
        • QE work-function calculation
        • Example: QE slab
        • Symmetric versus asymmetric slabs
        • Common problems
        • Scientific cautions
      • Charge-Density Difference
        • Important
        • Typical input
        • Open the CDD workflow
        • Cube-file information
        • Plot menu
        • 1. XY center slice
        • 2. XZ center slice
        • 3. YZ center slice
        • 4. All center slices
        • 5. Custom slice position
        • 6. Planar average along z
        • Color convention
        • Atomic overlays
        • Example: adsorption-system CDD
        • Generating the final QE CDD cube
        • 3D visualization
        • Interpreting CDD
        • Common problems
        • Scientific cautions
      • Electron Localization Function
        • Important
        • Open the ELF workflow
        • Existing ELF cube
        • No ELF cube found
        • Cube information
        • Plot menu
        • 1. XY center slice
        • 2. XZ center slice
        • 3. YZ center slice
        • 4. All center slices
        • 5. Custom slice position
        • ELF data files
        • Atomic overlays
        • Contour levels
        • Interpreting ELF
        • Example: bonding analysis
        • Example: Quantum ESPRESSO workflow
        • 3D visualization
        • Common problems
        • Scientific cautions
      • Bader Charge Analysis
        • Important
        • Typical required files
        • Open the Bader menu
        • 1. Check the executable and files
        • 2. Prepare the reference density
        • 3. Run Bader analysis
        • 4. Analyze an existing ACF.dat
        • Output file
        • Meaning of the columns
        • Example interpretation
        • Complete example workflow
        • Existing ACF.dat example
        • Common problems
        • Scientific cautions
      • AIMD / Trajectory Analysis
        • Required files
        • Open the AIMD menu
        • Time convention
        • Variable-cell trajectories
        • 1. Trajectory summary
        • 2. Atomic positions versus time
        • 3. Energy versus time
        • 4. Volume and lattice parameters versus time
        • 5. Bond distance versus time
        • 6. Mean-squared displacement
        • 7. Diffusion coefficient
        • 8. Radial distribution function
        • 9. Coordination number versus time
        • Example: Li-ion AIMD analysis
        • Recommended AIMD workflow
        • Scientific cautions
      • NEB / Transition-State Analysis
        • Important
        • Before starting
        • Open NEB image generation
        • VASP NEB preparation
        • VASP production setup
        • Quantum ESPRESSO NEB preparation
        • QE CIF inspection images
        • Running QE NEB
        • NEB post-processing
        • Expected directory layout
        • VASP energy detection
        • Quantum ESPRESSO energy detection
        • Mixed-code profiles
        • Relative-energy profile
        • Transition-state candidate
        • Forward activation barrier
        • Reverse activation barrier
        • Reaction energy
        • Generated NEB outputs
        • Example: VASP diffusion pathway
        • Example: QE NEB workflow
        • Common problems
        • Scientific cautions

Pre-processing

  • Pre-processing
    • Calculation Setup
      • Main setup workflows
      • Create a new calculation
        • VASP
        • Quantum ESPRESSO
      • CIF to input
      • Output to input
      • VASP setup checks
      • Quantum ESPRESSO setup checks
      • Pre-flight validation
      • Related pages
        • Input Generation
        • Reciprocal Space and Convergence
        • Pseudopotentials
        • Validation
        • Structure Editing
        • NEB Pre-processing
    • Structure Editing
      • Height and layer analysis
      • Layer detection
      • Supported input structures
        • VASP
        • Quantum ESPRESSO
      • [4] Freeze / fix atoms
        • VASP example
        • Quantum ESPRESSO example
      • Choose fixed direction
        • Examples
      • How VQkit represents constraints
        • VASP
        • Quantum ESPRESSO
      • Selecting atoms to fix
      • Selection by height
        • Example
        • Custom height
      • Selection by layers
      • Selection by atom index
      • Output file for freeze/fix workflow
        • VASP
        • Quantum ESPRESSO
      • Existing output protection
      • QE atom ordering and mapping
      • Example: freeze bottom two VASP layers
        • Step 1
        • Step 2
        • Step 3
        • Step 4
        • Step 5
        • Step 6
        • Step 7
      • Example: fix only z motion in QE
        • Step 1
        • Step 2
        • Step 3
        • Step 4
        • Step 5
      • [5] Delete atoms
        • Quantum ESPRESSO
        • VASP
      • Selecting atoms to delete
      • Selection by atom label/type
      • Selection by layers
      • Selection by height
      • Deletion summary
      • Delete-atoms output files
        • VASP
        • Quantum ESPRESSO
      • VASP deletion behavior
      • Quantum ESPRESSO deletion behavior
      • Example: remove an adsorbate
        • Step 1
        • Step 2
        • Step 3
        • Step 4
        • Step 5
        • Step 6
        • Step 7
      • Example: remove the top slab layer
        • Step 1
        • Step 2
        • Step 3
        • Step 4
        • Step 5
      • Important scientific checks after editing
        • After deletion
        • After freezing
      • Height-based selection cautions
      • Layer tolerance
      • Recommended workflow
    • Validation
      • Meaning of report levels
        • OK
        • WARNING
        • ERROR
        • INFO
      • Code detection
      • VASP pre-flight validation
      • INCAR checks
        • ENCUT
        • EDIFF
      • Repeated INCAR tags
      • Spin setup
      • Ionic-relaxation consistency
      • POSCAR checks
        • Cell volume
        • Species information
        • Selective dynamics
      • POTCAR checks
        • POSCAR versus POTCAR species order
        • POTCAR variants
      • ENCUT versus ENMAX
      • KPOINTS validation
        • Automatic mesh
        • Line mode
        • Explicit k points
      • HPC job script
      • VASP example report
      • Quantum ESPRESSO pre-flight validation
      • Required QE namelists
        • ELECTRONS namelist
      • nat and ntyp
      • ATOMIC_SPECIES
      • ATOMIC_POSITIONS
      • Lattice validation
      • Plane-wave cutoffs
      • K_POINTS validation
        • Automatic mesh
        • Band-structure path
      • Relaxation-specific checks
      • Smearing consistency
      • Calculation identity
      • pseudo_dir validation
      • Pseudopotential file validation
      • outdir
      • QE example report
      • READY logic
        • READY
        • READY WITH WARNINGS
        • NOT READY
      • What the checker does not validate
      • Recommended workflow
      • Scientific responsibility
    • Pseudopotentials
      • Why pseudopotential configuration matters
      • [8] Pseudopotential library setup
      • 1. Configure VASP POTCAR library
        • How VQkit finds a VASP library
        • Typical VASP library layouts
        • Exact element versus variant
      • 2. Configure Quantum ESPRESSO UPF library
        • QE pseudopotential availability
      • 3. Show configured pseudopotential libraries
      • 4. VQkit private pseudopotential folders
      • VASP licensing note
      • [7] Create POTCAR from POSCAR
        • Required file
        • Reading species information
        • Using a previously configured library
      • POTCAR assembly
      • Missing potential
      • Existing POTCAR
      • Automatic POTCAR creation during calculation setup
      • Example: VASP Fe-O calculation
        • Step 1 — Open Pre-processing
        • Step 2 — Create POTCAR
        • Step 3 — Confirm detected species
        • Step 4 — Select the local library
        • Step 5 — Resolve variants if necessary
        • Step 6 — Inspect the result
        • Step 7 — Run pre-flight validation
      • POTCAR and ENCUT
      • Example: Quantum ESPRESSO library setup
        • Step 1 — Open library setup
        • Step 2 — Select QE
        • Step 3 — Enter the path
        • Step 4 — Verify status
        • Step 5 — Use it in QE setup
      • Scientific selection of pseudopotentials
        • Exchange-correlation functional
        • Valence configuration
        • Spin-orbit coupling
        • Consistency across comparative calculations
        • Cutoff convergence
      • Common problems
        • VASP library not configured
        • Wrong directory level
        • POTCAR variant not selected
        • Missing QE UPF file
        • POSCAR species order changed
        • Existing POTCAR overwritten unintentionally
      • Licensing and redistribution
        • VASP
        • Quantum ESPRESSO
      • Recommended workflow
    • Reciprocal Space and Convergence
      • [9] Generate band-structure K-path
        • Supported structure sources
      • Symmetry tolerance scan
        • Why symprec matters
      • Symmetry-standardized path
      • Interpolation density
      • VASP path output
      • Quantum ESPRESSO path output
      • Built-in fallback path library
        • Simple cubic
        • Primitive FCC
        • Primitive BCC
        • Hexagonal
      • Band-path cautions
      • [10] K-points
      • Supported structures
        • VASP
        • Quantum ESPRESSO
      • Reciprocal lattice
      • Automatic k-spacing
      • Mesh formula
      • System dimensionality
      • Vacuum-gap estimation
      • Automatic dimensionality
      • 2D systems
      • 1D systems
      • 3D systems
      • Monkhorst-Pack mesh
      • Gamma-centered mesh
        • VASP output
        • Quantum ESPRESSO output
      • QE Monkhorst-Pack shifts
      • Irreducible k-points
        • VASP
        • Quantum ESPRESSO
      • Manual k-point mesh
      • K-point scientific cautions
        • Mesh density
        • Metals
        • DOS
        • Low-dimensional systems
        • Supercells
      • [11] Convergence tests
      • VASP cutoff preparation
        • Required files
        • Cutoff values
        • Output directory
      • Quantum ESPRESSO cutoff preparation
        • Default ecutwfc values
        • ecutrho ratio
        • Output structure
      • Execution modes
        • Prepare only
        • Generate HPC scripts
        • Run directly
      • Analyze completed cutoff calculations
      • Energy extraction
        • VASP
        • Quantum ESPRESSO
      • Reference energy
      • Recommended cutoff logic
      • Generated convergence outputs
      • Example: VASP cutoff convergence
        • Step 1
        • Step 2
        • Step 3
        • Step 4
        • Step 5
        • Step 6
        • Step 7
        • Step 8
      • Example: QE cutoff convergence
        • Step 1
        • Step 2
        • Step 3
        • Step 4
        • Step 5
        • Step 6
        • Step 7
        • Step 8
      • Convergence-test cautions
        • Only one parameter at a time
        • Geometry
        • Pseudopotential dependence
        • Property dependence
        • K-point convergence
      • Recommended workflow
    • NEB Pre-processing
      • NEB concept
      • Open the NEB image generator
      • VASP NEB preparation
        • Final structure
        • Number of intermediate images
        • Output folder
      • VASP endpoint requirements
      • VASP interpolation cautions
      • Recommended VASP workflow
      • Quantum ESPRESSO NEB preparation
        • Endpoint inputs
        • Endpoint consistency
        • Intermediate-image count
      • QE NEB output file
      • QE CIF inspection images
      • Visual validation
      • What to inspect in every image
      • QE execution
      • Review before running QE NEB
      • Climbing-image NEB
      • Number of images
        • Too few images
        • Too many images
      • Cell consistency
      • Periodic boundary conditions
      • Atom ordering
      • Endpoint optimization
      • VASP preparation after interpolation
      • Quantum ESPRESSO preparation after interpolation
      • NEB convergence
      • Transition-state interpretation
      • Recommended VASP example
        • Step 1
        • Step 2
        • Step 3
        • Step 4
        • Step 5
        • Step 6
        • Step 7
        • Step 8
        • Step 9
      • Recommended QE example
        • Step 1
        • Step 2
        • Step 3
        • Step 4
        • Step 5
        • Step 6
        • Step 7
        • Step 8
        • Step 9
        • Step 10
      • Connection to NEB post-processing
      • Scientific cautions
      • Recommended workflow

Post-processing

  • Post-processing
    • General Calculation Analysis
      • Example
      • Basic workflow
        • Step 1 — Enter the calculation directory
        • Step 2 — Open Post-processing
        • Step 3 — Choose General calculation analysis
      • Information reported
      • Code detection
        • VASP detection
        • Quantum ESPRESSO detection
        • Possible code labels
      • Calculation-type detection
        • VASP calculation types
        • Quantum ESPRESSO calculation types
      • VASP status detection
        • Completed
        • Converged / finalization not detected
        • Running or incomplete
        • No completed calculation detected
      • Quantum ESPRESSO status detection
        • QE XML sources
        • XML completion status
        • QE text-output status
      • Input/output association
      • VASP total-energy extraction
        • Meaning of the VASP energy
      • Quantum ESPRESSO total-energy extraction
      • VASP Fermi-level extraction
      • Quantum ESPRESSO Fermi-level extraction
      • Example: completed VASP SCF
      • Example: completed QE SCF
      • Example: incomplete calculation
      • Interpreting the status correctly
        • Completed
        • Converged / finalization not detected
        • Running or incomplete
        • Failed
      • Mixed directories
      • Why the summary is useful
      • Recommended post-processing sequence
      • Scientific cautions
        • Completion is not convergence
        • Last energy is not always the desired energy
        • Cross-code energy comparison
        • Fermi level interpretation
      • Summary limitations
      • Recommended practice
    • Structural Analysis
      • Overview
      • VASP example
      • Quantum ESPRESSO example
      • Final-structure detection
        • VASP
        • Quantum ESPRESSO
      • Optimized structure / lattice / volume
        • Lattice-vector lengths
        • Cell angles
        • Cell volume
        • Representative output
      • Converting the final structure to a new input
      • Bond-length analysis
        • Periodic boundary conditions
        • Distance calculation
        • Representative output
        • CSV output
      • Choosing a bond cutoff
      • Bond-angle analysis
        • Geometry
        • Representative output
        • CSV output
      • Atomic-height analysis
        • Projected coordinate
        • Representative output
        • CSV output
      • Layer analysis
        • Clustering logic
        • Representative output
        • CSV output
      • Using layer analysis for slab systems
      • Choosing the layer tolerance
      • Example: analyze a relaxed VASP slab
        • Step 1
        • Step 2
        • Step 3
        • Step 4
        • Step 5
        • Step 6
      • Example: analyze a relaxed QE structure
      • Minimum-image convention
      • Scientific cautions
        • Geometric cutoff is not a bond definition
        • Bond angles depend on the cutoff
        • Layer analysis assumes a-b is the surface plane
        • Final structure may not be converged
        • Cell changes matter
      • Recommended workflow
      • Generated files
    • Electronic Structure
      • General workflow
      • DOS - VASP
        • Energy reference
        • VASP DOS outputs
      • DOS - Quantum ESPRESSO
      • Projected DOS (PDOS)
        • Atom selection
        • Orbital groups
        • Spin-resolved PDOS
        • PDOS output filenames
      • Band structure - VASP
        • High-symmetry labels
      • Band structure - Quantum ESPRESSO
      • Band outputs
      • Spin-polarized bands
      • Band-gap analysis
        • Required data
        • Metallic / gapless classification
        • Semiconductor / insulator analysis
        • Direct gap
        • Representative output
        • Band-gap output
      • Band-gap cautions
      • Fermi energy
        • VASP
        • Quantum ESPRESSO
        • Representative output
      • Work function
        • VASP work function
        • Vacuum windows
        • Vacuum-flatness warning
      • Quantum ESPRESSO work function
        • QE potential units
      • Work-function outputs
      • Relationship between the six menu items
        • DOS
        • PDOS
        • Band structure
        • Band gap
        • Fermi energy
        • Work function
      • Recommended analysis sequence
      • Common cautions
        • Fermi-energy alignment
        • Spin polarization
        • DOS versus band gap
        • Band path
        • Work function
      • Generated files summary
        • DOS
        • PDOS
        • Band structure
        • Band gap
        • Work function
    • Charge Density, Bader Charge, and ELF
      • Charge-density difference
        • Preferred CDD filenames
        • No cube file found
      • CDD cube parsing
        • Density units
      • CDD plotting menu
        • Center slices
        • Custom slice
        • Planar average
      • CDD color convention
      • CDD outputs
      • Three-dimensional visualization
      • CDD interpretation cautions
      • Bader charge analysis
      • External dependency
      • Bader file-status check
      • Reference-density preparation
      • Running Bader analysis
        • Reference-density selection
      • Analyzing an existing ACF.dat
      • POTCAR ZVAL and net charge
        • Example
      • Bader output
      • Additional ACF information
      • Bader interpretation cautions
      • Electron localization function
        • Preferred filenames
      • ELF range
      • ELF plotting menu
        • Custom ELF slice
      • ELF contours
      • QE ELF preparation
      • ELF outputs
      • Three-dimensional ELF
      • Relationship between CDD, Bader, and ELF
        • CDD
        • Bader charge
        • ELF
      • Recommended combined workflow
      • Tutorial links
    • Energetics and Thermodynamics
      • Detected calculation and status
      • [1] Atom / molecule adsorption energy
        • General adsorption-energy expression
        • Isolated-atom reference
        • Molecular reference for atomic adsorption
        • Intact molecular adsorption
        • Adsorption-energy output
        • Adsorption-energy cautions
      • [2] Doping formation energy
        • Substitutional doping
        • Interstitial doping
        • Doping output
        • Chemical-potential caution
      • [3] NEB / transition-state analysis and plot
        • Expected directory layout
        • VASP image energies
        • Quantum ESPRESSO image energies
        • Mixed-code image sets
        • Relative energy
        • Transition-state candidate
        • Forward activation barrier
        • Reverse activation barrier
        • Reaction energy
        • NEB outputs
        • NEB scientific caution
      • [4] Surface energy
        • Surface treatment
        • Surface area
        • Energy inputs
        • Surface-energy units
        • Surface-energy output
        • Symmetric versus asymmetric slabs
      • [5] Single-atom vacancy formation energy
        • Vacancy output
        • Vacancy-energy caution
      • Common requirements for energetic comparisons
      • Energy versus free energy
      • Recommended workflow
      • Generated files summary
        • Adsorption
        • Doping
        • NEB
        • Surface energy
        • Vacancy
    • AIMD / Trajectory Analysis
      • General AIMD requirements
      • Time-step detection
      • Time convention
      • Variable-cell / NPT trajectories
      • Common XDATCAR prompt
      • Coordinate handling
      • Periodic unwrapping
      • [1] Trajectory summary
        • Output directory
        • Representative summary
      • [2] Atomic position coordinates vs time
        • Atom selection
        • Coordinate output
        • Output directory
        • Why unwrapped coordinates matter
      • [3] Energy vs time
        • OSZICAR parsing
        • OUTCAR fallback
        • Output directory
        • Scientific interpretation
      • [4] Volume / lattice parameters vs time
        • Output directory
      • [5] Bond distance vs time
        • Output directory
      • [6] Mean-square displacement (MSD)
        • Atom selection
        • MSD definition
        • Output directory
        • Variable-cell caution
      • [7] Diffusion coefficient
        • Einstein relation
        • Dimensionality
        • Fit range
        • Diffusion coefficient
        • Fit quality
        • Output directory
        • Diffusion-analysis caution
      • [8] Radial distribution function (RDF)
        • RDF definition
        • Maximum radius
        • Bin width
        • Output directory
        • RDF interpretation
      • [9] Coordination number vs time
        • Frame statistics
        • Output directory
        • Coordination cutoff
      • Atom and group selection
        • Position analysis
        • Group analyses
      • Example: Li-ion diffusion
        • Step 1
        • Step 2
        • Step 3
        • Step 4
        • Step 5
        • Step 6
        • Step 7
        • Step 8
      • Example: bond-breaking trajectory
      • Example: liquid structure
      • Output directory summary
        • Trajectory summary
        • Atomic positions
        • Energy
        • Cell / volume
        • Bond distance
        • MSD
        • Diffusion
        • RDF
        • Coordination
      • Plot generation
      • Important scientific cautions
        • Equilibration
        • Temperature stability
        • Trajectory length
        • Finite-size effects
        • Time-step choice
        • Variable-cell effects
        • Diffusion regime
      • Recommended AIMD analysis sequence
    • Batteries
      • Cathode material analysis
        • [1] Average Li insertion voltage
        • [2] Theoretical specific capacity
        • [3] Lithiation formation / tie-line energy
        • [4] Volume change on lithiation / delithiation
        • [5] Ideal specific-energy estimate
        • [6] Dilute-limit Li diffusivity estimate
        • [7] Cathode equations and reference
      • Anode material analysis
        • [1] Anode theoretical specific capacity
        • [2] Average Li intercalation voltage / OCV
        • [3] Carbon-anode formation energy
        • [4] Volume expansion on lithiation
        • [5] Li diffusion-barrier summary
        • [6] Anode equations and scientific notes
      • Chemical-formula mass parser
      • Reference consistency
      • Li metal reference
      • Formula-unit normalization
      • 0 K approximation
      • Cathode stability versus full phase stability
      • Diffusion caution
        • Cathode
        • Anode
      • Recommended cathode workflow
      • Recommended anode workflow
      • Connection to other VQkit modules
        • NEB
        • AIMD diffusion
        • Electronic structure
        • Structural changes
      • Current scope
      • Summary
        • Cathodes
        • Anodes
    • Catalysis
      • Computational hydrogen electrode
      • [1] ORR free-energy analysis (CHE)
        • Input modes
        • Adsorption free energies
        • CHE step spans
        • Limiting potential
        • ORR outputs
      • [2] OER free-energy analysis (CHE)
      • ORR/OER free-energy diagrams
      • [3] HER analysis
        • DFT adsorption energy
        • Thermochemical correction
        • Interpretation
        • HER outputs
      • [4] CO2RR analysis
        • CO pathway
        • Formate pathway
        • Potential and pH corrections
        • Limiting potential
      • [5] NRR analysis (CHE)
        • Incremental free energies
        • NRR outputs
        • Custom NRR pathway
      • [6] CO reduction (CORR) analysis
      • [7] Vibrational frequency analysis
        • Supported sources
        • Mode classification
        • Zero-point energy
        • Finite-temperature vibrational terms
        • Low-frequency cutoff
        • Outputs
        • Imaginary-mode caution
      • [8] Orbital center (s/p/d)
        • Spin-polarized calculations
        • Integration windows
        • Atom selection
        • Required VASP data
        • Output
        • Current backend scope
        • Comparison rule
      • Catalysis workflow relationships
        • Electronic structure
        • Charge and bonding
        • Reaction barriers
        • AIMD
      • Recommended ORR/OER workflow
      • Recommended HER workflow
      • Recommended CO2RR workflow
      • Recommended NRR/CORR workflow
      • Thermochemistry consistency
      • Scientific limitations
      • Summary
    • Mechanical / Structural Properties
      • Elastic tensor
      • Voigt strain convention
      • Default strain grid
      • [1] Prepare elastic calculations
      • Source structures
      • Metric lattice-family detection
      • General elastic mode
      • Symmetry-reduced mode
      • Energy-strain method
        • Energy-strain physics
      • VASP preparation
      • Quantum ESPRESSO preparation
      • Output directories
      • Manifest file
      • Stress-strain method
      • Stress-strain accuracy
      • [2] Analyze completed elastic calculations
      • Energy-strain fitting
      • Stress-strain fitting
      • Raw stress stiffness tensor
      • Elastic stiffness tensor
      • Compliance tensor
      • Voigt-Reuss-Hill properties
        • Young’s modulus
        • Poisson ratio
        • Pugh ratio
      • Elastic anisotropy
      • Mechanical stability
      • Mechanical output summary
      • [3] Directional elasticity: high-accuracy 3D plots
        • Input sources
      • Positive-definite requirement
      • Young’s modulus
      • Linear compressibility
      • Shear modulus
      • Poisson ratio
      • High-resolution grid
      • ELATE-compatible optimization
      • Automatic directional extrema
      • Directional output directory
      • Directional summary
      • Recommended elastic workflow
      • Energy-strain versus stress-strain
        • Energy-strain
        • Stress-strain
      • Scientific cautions
        • Small-strain regime
        • Internal relaxation
        • Symmetry
        • Convergence
        • Stability
      • Summary
    • Phonon-Derived Transport Properties
      • [1] Phonon group velocity
      • Supported dispersion-table formats
        • Phonopy band.dat
        • Rectangular table
        • Simple branch-block table
      • Source-unit selection
      • Group-velocity conversion
      • Segment-aware differentiation
      • Branch-resolved velocities
      • Acoustic-mode estimate near Gamma
        • Representative output
      • Acoustic RMS velocity
      • Group-velocity cautions
      • [2] Gruneisen parameter
        • Gruneisen menu
      • [1] gruneisen_band.dat
      • Acoustic RMS Gruneisen parameter
      • Two-volume Gruneisen calculation
      • Non-positive frequencies
      • Folder-based workflow
      • Volume-span warning
      • Gruneisen outputs
      • Scientific interpretation
      • [3] Debye temperature
      • Automatic Debye workflow
        • Acoustic velocity
        • Structure detection
      • Velocity-based Debye temperature
      • Automatic Debye output
      • Maximum-frequency estimate
      • Manual acoustic-velocity mode
      • Relationship among the three descriptors
        • Group velocity
        • Gruneisen parameter
        • Debye temperature
      • Recommended workflow
      • Scientific cautions
        • Phonon stability
        • q-path dependence
        • Acoustic fitting
        • Volume perturbation
        • Branch correspondence
        • Debye-model limitation
        • Thermal conductivity
      • Generated files summary
        • Group velocity
        • Acoustic Gruneisen RMS
        • Mode-resolved Gruneisen parameter
        • Debye temperature
      • Summary
    • Supercapacitor
      • [1] Quantum capacitance from DOS
      • DOS source
        • VASP
        • Quantum ESPRESSO
      • Spin-polarized DOS
      • Fermi-Dirac derivative
      • Effective DOS
      • Area conversion
      • Electrode-area input
        • Automatic structure detection
        • Manual area
      • Temperature
      • Potential modes
        • Single potential
        • Potential range
      • Potential-dependent output
      • Quantum-capacitance summary
      • Plots
      • Low-temperature limit
      • Example quantum-capacitance workflow
        • Step 1
        • Step 2
        • Step 3
        • Step 4
        • Step 5
        • Step 6
        • Step 7
        • Step 8
      • [2] Total interfacial capacitance
      • Input
      • Physical interpretation
      • [3] Show equations / conventions
      • Quantum capacitance versus double-layer capacitance
        • Quantum capacitance
        • Double-layer capacitance
      • DOS convergence
      • Energy window
      • Electrode area
      • One-sided versus two-sided electrodes
      • Potential convention
      • Temperature dependence
      • Supercapacitor limitations
      • Pseudocapacitive materials
      • Recommended workflow
      • Connection to other VQkit modules
        • Electronic DOS
        • Structural area
        • Charge redistribution
      • Generated files summary
        • Quantum capacitance data
        • Quantum capacitance summary
        • Potential-dependent plot
      • Summary

Reference

  • Gallery
    • Pre-processing examples
      • Calculation preparation
        • VASP calculation setup
        • Quantum ESPRESSO calculation setup
      • Band-structure preparation
      • NEB preparation
    • Post-processing examples
      • General calculation analysis
      • Structural analysis
    • Electronic structure
      • Density of states
      • Band structure
      • Work function
    • Additional gallery topics
  • Resources
    • Electronic-structure software
      • VASP
      • Quantum ESPRESSO
    • Scientific Python ecosystem
      • NumPy
      • SciPy
      • Matplotlib
      • spglib
      • SeeK-path
    • Related tools
    • Pseudopotential resources
    • Documentation resources
    • Licensing and citation
  • Citation
  • Downloads
    • Current release
      • VQkit 1.1
        • Recommended installation package
        • Installable wheel
        • Source distribution
        • Source ZIP
        • Complete software package
    • Package selection
    • Official download location
    • Verification
  • Release Notes
    • VQkit 1.0
  • Acknowledgments
    • Electronic-structure software
    • Scientific Python ecosystem
    • Development and testing
    • Community
    • Citation and third-party software
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