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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 (Dct)
  • 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