| name | gaussian |
| version | 2.0.0 |
| description | Gaussian 16 quantum chemistry software. Electronic structure calculations, geometry optimization, frequency analysis, TDDFT excited states, and more. Based on official Gaussian.com documentation. |
| homepage | https://gaussian.com |
| metadata | {"category":"computational_chemistry","tags":["quantum_chemistry","DFT","TDDFT","frequency","optimization","excited_states","ab_initio"]} |
Gaussian 16 — Quantum Chemistry Software
Overview
Gaussian is the industry-standard quantum chemistry software for electronic structure calculations. It supports DFT (all major functionals), HF, MPn, CCSD(T), CASSCF, TDDFT, geometry optimization, frequency analysis, reaction pathways, and much more.
Installed on: marcus HPC cluster (remote server access via marcus2)
Connection
ssh -p 8722 openclaw@124.16.75.110
ssh marcus
module load gaussian/g16.c01-avx2
Input File Format (.gjf)
%chk=filename.chk # Checkpoint file
%mem=60GB # Memory allocation
%nproc=64 # Number of CPU cores
# route_section # Method, basis set, job type, options
Title
Charge SpinMultiplicity # Molecular charge and spin (0 1 = neutral singlet)
Cartesian or Z-Matrix coordinates
Link0 Commands
| Command | Description |
|---|
%chk=file.chk | Checkpoint file path |
%mem=60GB | Memory (any unit: MB, GB) |
%nproc=64 | CPU cores |
%nprocshared=32 | Shared memory parallelism |
%oldchk=file.chk | Continue from existing checkpoint |
%save | Force checkpoint saving |
Job Types
| Keyword | Description | Common Options |
|---|
SP | Single-point energy | Default calculation |
Opt | Geometry optimization | Opt=CalcFC, Opt=TS, Opt=Tight, Opt=MaxStep=N |
Freq | Frequency analysis | Freq=Raman, Freq=HPC |
Opt Freq | Optimize then compute frequencies | Verify minima/transition states |
Scan | Potential energy surface scan | Scan=ModRedundant, Scan=Bond, Scan=Angle |
IRC | Intrinsic reaction coordinate | Follow reaction path from TS |
Polar | Polarizability | Polar=EnOnly |
ADMP | Car-Parrinello molecular dynamics | |
BOMD | Born-Oppenheimer MD | |
stable | Wavefunction stability test | |
Methods
Hartree-Fock
# HF/6-31G*
HF — Restricted (RHF), UHF — Unrestricted, ROHF — Restricted open-shell
DFT Functionals
| Functional | Type | HF Exchange | Notes |
|---|
B3LYP | Hybrid GGA | 20% | Most popular, good all-round |
PBE0 | Hybrid GGA | 25% | Based on PBE, reliable |
M06-2X | Meta-GGA hybrid | 54% | Good for non-covalent, thermochemistry |
M06 | Meta-GGA hybrid | 27% | Minnesota functional |
CAM-B3LYP | Range-separated hybrid | Variable | Long-range corrected |
WB97X-D | Range-separated + D3 | Variable | Dispersion-corrected |
WB97X-D3BJ | Range-separated + D3(BJ) | Variable | Better dispersion |
LC-WPBE | Long-range corrected | 100% at long range | Charge-transfer states |
wPBE | Long-range corrected | 100% at long range | Same as LC-WPBE |
TPSSH | Hybrid meta-GGA | 10% | |
BP86 | GGA | 0% | |
PBE | GGA | 0% | |
BLYP | GGA | 0% | |
SVWN5 | LDA | 0% | |
HSEHJS | Range-separated | 50% at short range | Screened Coulomb |
Wave Function Methods
| Method | Description |
|---|
MP4 | 4th-order Møller-Plesset perturbation |
MP3 | 3rd-order MP |
MP2 | 2nd-order MP (also MP2=Full) |
CCSD | Coupled-cluster singles + doubles |
CCSD(T) | CCSD with perturbative triples |
CCSD=T | CCSD with full triples (non-perturbative) |
CCD, CCSD, CID, CISD | Other coupled-cluster variants |
CASSCF(n,m) | Complete active space SCF (n electrons, m orbitals) |
CASPT2 | Multi-state second-order perturbation |
EOMCCSD | Equation-of-motion CCSD (excited states) |
SAC-CI | Symmetry-adapted cluster CI |
GVB | Generalized valence bond |
CIS | Configuration interaction singles |
CIS(D) | CIS with perturbative doubles |
Semi-Empirical
# CNDO, INDO, MINDO3, MNDO, AM1, PM3, ZINDO
Basis Sets
Pople Split-Valence
| Basis | Description |
|---|
STO-3G | Minimal basis (fast) |
3-21G | Split-valence, lightest |
6-21G | Pople split-valence |
6-31G | Double-zeta, standard for organics |
6-31G* | With polarization on heavy atoms |
6-31G** | With polarization on all atoms |
6-31+G* | With diffusion on heavy atoms |
6-31++G** | With diffusion on all |
6-311G | Triple-zeta |
6-311G* | Triple-zeta + polarization |
6-311++G(2d,2p) | Highly extended |
Correlation-Consistent (cc-pVnZ)
cc-pVDZ, cc-pVTZ, cc-pVQZ, cc-pV5Z, cc-pV6Z
aug-cc-pVDZ, aug-cc-pVTZ, aug-cc-pVQZ # Augmented with diffuse functions
Def2 / Karlsruhe
def2-SVP, def2-TZVP, def2-QZVP
def2-TZVPP — with polarization functions
Effective Core Potentials (ECPs)
| ECP | Description |
|---|
LANL2DZ | Los Alamos ECP + DZ basis |
LANL2DZdp | LANL2DZ with polarization |
Stuttgart | Stuttgart-Cologne ECPs |
CRENBL | Relativistic ECP |
Other
| Basis | Description |
|---|
cc-pCVnZ | Core-valence (for core excitations) |
pc-n | Polarization consistent basis |
pcseg-n | Segmented polarization consistent |
N07D | Density-fitting basis sets |
TDDFT — Excited States
# td=(nstates=10,root=1,singlets) b3lyp/6-31G*
# td=(nstates=10,triplets) b3lyp/6-31G* # Triplet states only
Options:
nstates=N — Number of excited states (default 10)root=N — Optimize/persist on state Nsinglets — Singlet excitations (default)triplets — Triplet excitationsalltrans — Include all triplet-singlet transitions50-50 — 50% CI coefficients for each determinant50-50TDDFT — Special for degenerate states
For vertical emission:
# td=(nstates=5,singlets) b3lyp/6-31G* # Excitation
# b3lyp/6-31G* td=(root=1) geom=check # Emission from S1
Solvent Effects (SCRF)
# b3lyp/6-31G* scrf=(smd,solvent=acetonitrile)
# b3lyp/6-31G* scrf=(pcm,solvent=water)
SCRF Models:
| Model | Keyword | Notes |
|---|
| PCM | SCRF=PCM | Polarizable continuum |
| SMD | SCRF=SMD | Solvent model based on density (G16 default) |
| CPMF | SCRF=CM5 | |
| HCTH | SCRF=HCTH | |
| SWIG | SCRF=SWIG | |
Common Solvents: water, ethanol, methanol, acetonitrile, dmso, dmf, chloroform, toluene, benzene, diethylether, thf, acetone
Geometry Optimization Options
# opt=calcfc # Compute force constants initially (default for TS)
# opt=ts # Transition state search
# opt=tight # Tight convergence criteria
# opt=gdiis # Use GDIIS for optimization
# opt=modredundant # Modredundant coordinates
# opt=maxstep=n # Maximum step size (default 0.3 bohr)
# opt=readvariance # Read variance data
# freq=hpc # HPC-mode frequency scaling
ModRedundant examples (in input):
C 1 2 R # Define bond between atoms 1-2
D 1 2 3 4 180.0 F # Scan dihedral angle 1-2-3-4 to 180°
Frequency Options
# freq=hindered rotor # Include hindered rotor corrections
# freq=raman # Raman activity
# freq=check # Read frequency data from checkpoint
# freq=(hinderedrot,temperature=298.15,pressure=1.0)
Population Analysis
# pop=full # Full AO/MO analysis
# pop=full,nbomo # Include NBOs
# pop=nbo # Natural Bond Orbital analysis
# pop=npa # Natural Population Analysis
# pop=mk # Merz-Kollman ESP charges
# pop=chelpg # CHELPG ESP charges
# pop=(bondorder) # Wiberg/Mayer bond order
# pop=density # Output density matrices
NMR Properties
# nmr=cpa # Continuous set of gauge transformations
# nmr=spin-spin # Spin-spin coupling constants
# spinnuclear= # Specify magnetic nuclei
# mag= # Magnetic properties
SCF Convergence
# scf=qc # Quadratic convergence (most robust)
# scf=xqc # Extra quadratic convergence (try QC if this fails)
# scf=diis # DIIS (default)
# scf=maxcyc=n # Max SCF cycles (default 128)
# scf=conver=n # Convergence criterion (10^-n)
# scf=tight # Tight SCF convergence
# scf=novariational # Non-variational MOs
# scf=direct # Direct SCF (on-the-fly integral recomputation)
# scf=fermi # Fermi-VWN5 for metals
CBS Extrapolation
# cbs=QB3 # CBS-QB3 composite method
# cbs=APF # CBS-APF method
# cbs=4s # 4-parameter CBS extrapolation
# CBSExtrapolate=2/3 # Two-point extrapolation n=2,3
Composite Methods:
| Method | Description |
|---|
CBS-QB3 | CBS-QB3 composite |
CBS-APF | CBS-APF composite |
W1U | W1 ultra-fine |
W1 | W1 method |
W2 | W2 method |
W3 | W3 method |
W4 | W4 method |
CBS-4s | CBS with 4-parameter extrapolation |
G1 | G1 composite |
G2 | G2 composite |
G3 | G3 composite |
G4 | G4 composite |
IRC (Intrinsic Reaction Coordinate)
# irc=kalida # Use Kupidonov-Khailenko algorithm
# irc=gs2 # Gonzalez-Schlegel second-order algorithm (default)
# irc=nproc=n # Points per process in IRC
# ircmax=n # Maximum points in IRC path
External Potentials / Basis
# ExtraBasis=file # Additional basis functions
# Gen # User-defined basis in input
# GenECP # User-defined ECP in input
# Pseudo=read # Read ECP from checkpoint
# densityfit # Use density fitting (DF) for efficiency
# nodensityfit # Disable density fitting
Wavefunction Analysis
# Density=current # Use current density
# guess=modify,alter # Modify/alter initial MOs
# guess=hop # Hückel initial guess
# guess=read # Read MOs from checkpoint
# stable=opt # Optimize unstable wavefunction
# prop=flex # Flexible property output
Stabilty Analysis
# stable # Test wavefunction stability
# stable=opt # Optimize to stable wavefunction
Common Task Templates
Ground-State Optimization + Frequency
%chk=opt_freq.chk
%mem=60GB
%nproc=64
# opt freq b3lyp/6-31G**
Molecule optimization
0 1
C 0.0 0.0 0.0
...
TDDFT Excited States
%chk=tddft.chk
%mem=60GB
%nproc=64
# td=(nstates=10,singlets) b3lyp/6-31G*
S1 vertical excitations
0 1
C 0.0 0.0 0.0
...
S1 Optimization + Vertical Emission
%chk=s1_opt.chk
%mem=60GB
%nproc=64
# td=(nstates=5,root=1) b3lyp/6-31G* opt
S1 optimization
0 1
... (ground-state optimized geometry)
%chk=emission.chk
%mem=60GB
%nproc=64
# b3lyp/6-31G* td=(root=1) geom=check
S1 vertical emission
0 1
... (S1 optimized geometry)
Solvent Effect (SMD)
%chk=smd.chk
%mem=60GB
%nproc=64
# b3lyp/6-31G* scrf=(smd,solvent=acetonitrile)
SMD solvent model
0 1
...
CBS-QB3 Composite
%chk=cbs-qb3.chk
%mem=60GB
%nproc=64
# cbs-qb3
CBS-QB3 calculation
0 1
...
CASSCF
%chk=cas.chk
%mem=60GB
%nproc=64
# casSCF(10,8)/6-31G*
CAS(10,8) — 10 electrons, 8 orbitals in active space
0 1
...
ModRedundant Scan
%chk=scan.chk
%mem=60GB
%nproc=64
# b3lyp/6-31G* opt=modredundant
Dihedral scan
0 1
C 0 0 0
C 1 2 1.4
...
1 2 3 4 90.0 S 20 5.0 # Scan dihedral 1-2-3-4, 20 steps, 5° each
Useful IOp Values
| IOp | Description |
|---|
IOp(3/76=055000) | Scale HF exchange in hybrid functionals |
IOp(3/77=055000) | Scale correlation |
IOp(3/78=...) | DFT integration grid |
IOp(5/33=...) | Frozen core approximation |
IOp(5/34=...) | Use spherical harmonics |
IOp(5/41=...) | Population analysis options |
Converting Checkpoint Files
formchk filename.chk filename.fchk
unfchk filename.chk filename.fchk
Output Files
| Extension | Description |
|---|
.log | Main output file |
.chk | Binary checkpoint file |
.fchk | Formatted ASCII checkpoint |
.out | (sometimes used) |
.cub | Cube file for visualization |
.int | Two-electron integrals |
.sbn | Scratch binary file |
Official Keyword Index
Full keyword list from gaussian.com/keywords/:
ADMP, BD, BOMD, CacheSize, CASSCF, CBS Methods, CBSExtrapolate, CCD and CCSD, Charge, ChkBasis, CID and CISD, CIS, CNDO, Complex, Constants, Counterpoise, CPHF, Density, DensityFit and NoDensityFit, DFT Methods, DFTB and DFTBA, EET, EOMCCSD, EPT, External, ExtraBasis & ExtraDensityBasis, Field, FMM, Force, Freq, Gen and GenECP, GenChk, Geom, GFInput, GFPrint, Gn Methods, Guess, GVB, HF, Huckel, INDO, Integral, IOp, IRC, IRCmax, Link0 Commands, LSDA, MaxDisk, MINDO3, MNDO, MM Methods, MP Methods, Name, NMR, ONIOM, Opt, Output, PBC, Polar, Population, Pressure, Prop, Pseudo, Punch, QCI, Restart, SAC-CI, Scale, Scan, SCF, SCRF, Semi-Empirical Methods, SP, Sparse, Stable, Symmetry, TD, Temperature, Test, TestMO, TrackIO, Transformation, Units, Volume, W1 Methods, Window Keyword and Frozen Core Options, ZIndo
Advanced Topics
###ONIOM (Embedded Fragment)
# oniom(b3lyp/6-31G*:pm3)=(...)
Layer definition in molecule section:
H -1 0.0 0.0 0.0 q=0 # High layer
L 0 0.0 0.0 0.0 q=+1 # Low layer
...
EOM-CCSD (Excited States / Ionization)
# eomccsd # EOM-CCSD for excited states
# eom(ip) # Ionization potentials
# eom(ea) # Electron affinities
# eom(ee) # Two-electron excitations
Density Fitting
# densityfit # Enable DF for all calculations
# scf=(nodensityfit) # Disable DF for SCF only
# mp2=fulldensityfit # Full density fitting for MP2
PBC (Periodic Boundary Conditions)
# pbc载体 # Enable PBC calculations
# pbe0/pcs Solvent=... # With SCRF
