Gaussian Features at a Glance

Features introduced since Gaussian 09 Rev A are in blue.
Existing features enhanced in Gaussian 16 are in green.

Fundamental Algorithms

• Calculation of one- & two-electron integrals over any contracted gaussian functions
• Conventional, direct, semi-direct and in-core algorithms
• Linearized computational cost via automated fast multipole methods (FMM) and sparse matrix techniques
• Harris initial guess
• Initial guess generated from fragment guesses or fragment SCF solutions
• Density fitting and Coulomb engine for pure DFT calculations, including automated generation of fitting basis sets
•  exact exchange for HF and hybrid DFT
• 1D, 2D, 3D periodic boundary conditions (PBC) energies & gradients (HF & DFT)
• Shared-memory (SMP), cluster/network and GPU-based parallel execution

Model Chemistries

Molecular Mechanics

• Amber, DREIDING and UFF energies, gradients, and frequencies
  • Custom force fields
• Standalone MM program

Ground State Semi-Empirical

• CNDO/2, INDO, MINDO3 and MNDO energies and gradients
• AM1, PM3, PM3MM, PM6 and PDDG energies, gradients and reimplemented (analytic) frequencies
• PM7: original and modified for continuous potential energy surfaces
• Custom semi-empirical parameters (Gaussian and MOPAC External formats)
• DFTB and DFTBA methods

Self Consistent Field (SCF)

• SCF restricted and unrestricted energies, gradients and frequencies, and RO energies and gradients
• EDIIS+CDIIS default algorithm; optional Quadratic Convergent SCF
• SCF procedure enhancements for very large calculations
• Complete Active Space SCF (CASSCF) energies, gradients & frequencies
  • Active spaces of up to 16 orbitals
• Restricted Active Space SCF (RASSCF) energies and gradients
• Generalized Valence Bond-Perfect Pairing energies and gradients
• Wavefunction stability analysis (HF & DFT)

Density Functional Theory

Closed and open shell energies, gradients & frequencies, and RO energies & gradients are available for all DFT methods.

• EXCHANGE FUNCTIONALS: Slater, Xα, Becke 88, Perdew-Wang 91, Barone-modified PW91, Gill 96, PBE, OPTX, TPSS, revised TPSS, BRx, PKZB, ωPBEh/HSE, PBEh
• CORRELATION FUNCTIONALS: VWN, VWN5, LYP, Perdew 81, Perdew 86, Perdew-Wang 91, PBE, B95, TPSS, revised TPSS, KCIS, BRC, PKZB, VP86, V5LYP
• OTHER PURE FUNCTIONALS: VSXC, HCTH functional family, τHCTH, B97D, M06L, SOGGA11, M11L, MN12L, N12, MN15L
• HYBRID METHODS: B3LYP, B3P86, P3PW91, B1 and variations, B98, B97-1, B97-2, PBE1PBE, HSEh1PBE and variations, O3LYP, TPSSh, τHCTHhyb, BMK, AFD, M05, M052X, M06, M06HF, M062X, M08HX, PW6B95, PW6B95D3, M11, SOGGA11X, N12, MN12SX, N12SX, MN15, HISSbPBE, X3LYP, BHandHLYP; user-configurable hybrid methods
• DOUBLE HYBRID: B2PLYP & mPW2PLYP and variations with dispersion, DSDPBEP86, PBE0DH, PBEQIDH (see also below in "Electron Correlation")
• EMPIRICAL DISPERSION: PFD, GD2, GD3, GD3BJ
• FUNCTIONALS INCLUDING DISPERSION: APFD, B97D3, B2PLYPD3
• LONG RANGE-CORRECTED: LC-ωPBE, CAM-B3LYP, ωB97XD and variations, Hirao's general LC correction
• Larger numerical integrations grids

Electron Correlation

All methods/job types are available for both closed and open shell systems and may use frozen core orbitals; restricted open shell calculations are available for MP2, MP3, MP4 and CCSD/CCSD(T) energies.

• MP2 energies, gradients, and frequencies
• Double hybrid DFT energies, gradients and frequencies, with optional empirical dispersion (see list in "Density Functional Theory" above)
• CASSCF calculations with MP2 correlation for any specified set of states
• MP3 and MP4(SDQ) energies and gradients
• MP4(SDTQ) and MP5 energies
• Configuration Interaction (CISD) energies & gradients
• Quadratic CI energies & gradients; QCISD(TQ) energies
• Coupled Cluster methods: restartable CCD, CCSD energies & gradients, CCSD(T) energies; optionally input amplitudes computed with smaller basis set
  • Optimized memory algorithm to avoid I/O during CCSD iterations
• Brueckner Doubles (BD) energies and gradients, BD(T) energies; optionally input amplitudes & orbitals computed with a smaller basis set
• Enhanced Outer Valence Green's Function (OVGF) methods for ionization potentials & electron affinities
• Complete Basis Set (CBS) MP2 Extrapolation
• Douglas-Kroll-Hess scalar relativistic Hamiltonians

Automated High Accuracy Energies

• G1, G2, G3, G4 and variations
• CBS-4, CBS-q, CBS-QB3, ROCBS-QB3, CBS-Q, CBS-APNO
• W1U, W1BD, W1RO (enhanced core correlation energy calculation)

Basis Sets and DFT Fitting Sets

• STO-3G, 3-21G, 6-21G, 4-31G, 6-31G, 6-31G†, 6-311G, D95, D95V, SHC, CEP-nG, LanL2DZ, cc-pV{D,T,Q,5,6}Z, Dcc-p{D,T}Z, SV, SVP, TZV, QZVP, EPR-II, EPR-III, Midi!, UGBS*, MTSmall, DG{D, T}ZVP, CBSB7
  • Augmented cc-pV*Z schemes: Aug- prefix, spAug-, dAug-, Truhlar calendar basis sets (original and regularized)
• Effective Core Potentials (through second derivatives): LanL2DZ, CEP through Rn, Stuttgart/Dresden
• Support for basis functions and ECPs of arbitrary angular momentum
• DFT FITTING SETS: DGA1, DGA1, W06, older sets designed for SVP and TZVP basis sets; auto-generated fitting sets; optional default enabling of density fitting

Geometry Optimizations and Reaction Modeling

• Geometry optimizations for equilibrium structures, transition structures, and higher saddle points, in redundant internal, internal (Z-matrix), Cartesian, or mixed internal and Cartesian coordinates
• GEDIIS optimization algorithm
• Redundant internal coordinate algorithm designed for large system, semi-empirical optimizations
• Newton-Raphson and Synchronous Transit-Guided Quasi-Newton (QST2/3) methods for locating transition structures
• IRCMax transition structure searches
• Relaxed and unrelaxed potential energy surface scans
• Implementation of intrinsic reaction path following (IRC), applicable to ONIOM QM:MM with thousands of atoms
• Reaction path optimization
• BOMD molecular dynamics (all analytic gradient methods); ADMP molecular dynamics: HF, DFT, ONIOM(MO:MM)
• Optimization of conical intersections via state-averaged CASSCF
• Generalized internal coordinates for complex optimization constraints

Vibrational Frequency Analysis

• Vibrational frequencies and normal modes (harmonic and anharmonic), including display/output limiting to specified atoms/residues/modes (optional mode sorting)
• Restartable analytic HF and DFT frequencies
• MO:MM ONIOM frequencies including electronic embedding
• Analytic Infrared and static and dynamic Raman intensities (HF & DFT; MP2 for IR)
• Pre-resonance Raman spectra (HF and DFT)
• Projected frequencies perpendicular to a reaction path
• NMR shielding tensors & GIAO magnetic susceptibilities (HF, DFT, MP2) and enhanced spin-spin coupling (HF, DFT)
• Vibrational circular dichroism (VCD) rotational strengths (HF and DFT; harmonic and anharmonic)
• Dynamic Raman Optical Activity (ROA) intensities (harmonic and anharmonic)
• Raman and ROA intensities calculated separately from force constants in order to use a larger basis set
• Harmonic vibration-rotation coupling
• Enhanced anharmonic vibrational analysis, including IR intensities, DCPT2 & HDCPT2 method for resonance-free computations of anharmonic frequencies
• Anharmonic vibration-rotation coupling via perturbation theory
• Hindered rotor analysis

Molecular Properties

• Population analysis, including per-orbital analysis for specifed orbitals: Mulliken, Hirshfeld, CM5
• Computed atomic charges can be saved for use in a later MM calculation
• Electrostatic potential, electron density, density gradient, Laplacian, and magnetic shielding & induced current densities over an automatically generated grid
• Multipole moments through hexadecapole
• Biorthogonalization of MOs (producing corresponding orbitals)
• Electrostatic potential-derived charges (Merz-Singh-Kollman, CHelp, CHelpG, Hu-Lu-Yang)
• Natural orbital analysis and natural transition orbitals
• Natural Bond Orbital (NBO) analysis, including orbitals for CAS jobs. Integrated support for NBO3; external interface to NBO6
• Static and frequency-dependent analytic polarizabilities and hyperpolarizabilities (HF and DFT); numeric 2nd hyperpolarizabilities (HF; DFT w/ analytic 3rd derivs.)
• Approx. CAS spin orbit coupling between states
• Enhanced optical rotations and optical rotary dispersion (ORD)
• Hyperfine spectra components: electronic g tensors, Fermi contact terms, anisotropic Fermi contact terms, rotational constants, dipole hyperfine terms, quartic centrifugal distortion, electronic spin rotation tensors, nuclear electric quadrupole constants, nuclear spin rotation tensors
• ONIOM integration of electric and magnetic properties

ONIOM Calculations

• Enhanced 2 and 3 layer ONIOM energies, gradients and frequencies using any available method for any layer
• Optional electronic embedding for MO:MM energies, gradients and frequencies implemented so as to include all effects of the MM environment without neglecting terms in its coupling with the QM region
• Enhanced MO:MM ONIOM optimizations to minima and transition structures via microiterations including electronic embedding
• Support for IRC calculations
• ONIOM integration of electric and magnetic properties

Excited States

• ZINDO energies
• CI-Singles energies, gradients, & freqs.
• Restartable time-dependent (TD) HF & DFT energies, gradients and frequencies. TD-DFT can use the Tamm-Dancoff approximation.
• SAC-CI energies and gradients
• EOM-CCSD energies and gradients (restartable); optionally input amplitudes computed with a smaller basis set
• Franck-Condon, Herzberg-Teller and FCHT analyses
• Vibronic spectra including electronic circular dichroism (ECD) rotational strengths (HF and DFT)
• Resonance Raman spectra
• Ciofini's excited state charge transfer diagnostic (D_ct)
• Caricato's EOMCC solvation interaction models
• CI-Singles and TD-DFT in solution
• State-specific excitations and de-excitations in solution
• An energy range for excitations can be specified for CIS and TD excitation energies

Self-Consistent Reaction Field Solvation Models

• New implementation of the Polarized Continuum Model (PCM) facility for energies, gradients and frequencies
• Solvent effects on vibrational spectra, NMR, and other properties
• Solvent effects for ADMP trajectory calcs.
• Solvent effects for ONIOM calculations
• Enhanced solvent effects for excited states
• SMD model for ΔG of solvation
• Other SCRF solvent models (HF & DFT): Onsager energies, gradients and freqs., Isodensity Surface PCM (I-PCM) energies and Self-Consistent Isodensity Surface PCM (SCI-PCM) energies and gradients

Ease-of-Use Features

• Automated counterpoise calculations
• Automated optimization followed by frequency or single point energy
• Ability to easily add, remove, freeze, differentiate redundant internal coords.
• Simplified isotope substitution and temperature/pressure specification in the route section
• Optimizations
  • Retrieve the nth geometry from a checkpoint file
  • Recompute the force constants every nth step of a geometry optimization
  • Reduce the maximum number of allowed steps, including across restarts
  • 180° flips detected and suppressed for better visualization
• Freezing by fragment for ONIOM optimizations
• Simplified fragment definitions on molecule specifications
• Many more restartable job types
• Atom freezing in optimizations by type, fragment, ONIOM layer and/or residue
• QST2/QST3 automated transition structure optimizations
• Saving and reading normal modes
• %OldChk Link 0 command specifies read-only checkpoint file for data retrieval
• Default.Route file for setting calculation defaults
• Enhanced set of equivalent Default.Route directives, Link 0 commands, command line options and environment variables

Integration with External Programs

• NBO 6
• COSMO/RS
• AIMPAC WfnX files
• Antechamber
• ACID
• Pickett's program
• DFTB input file
• General external interface script-based automation, results post-processing, interchanging data/calculation results with other programs, and so on:
  • Interface routines in Fortran, Python and Perl (open source)
  • Keyword and Link 0 command support