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