Several new DFT functional options:
Long-ranged-corrected (LRC) functionals
Baer-Neuhauser-Livshits (BNL) functional
Variations of ?B97 Functional
Constrained DFT (CDFT)
Grimme’s empirical dispersion correction
Solvation models:
SM8 model (energy and analytical gradient) for water and organic solvents
Updates to Onsager reaction-field model
Intermolecular interaction analysis:
SCF with absolutely localized molecular orbitals for molecule interaction (SCF-MI)
Roothaan-step (RS) correction following SCF-MI
Energy decomposition analysis (EDA)
Complementary occupied-virtual pair (COVP) analysis for charge transfer
Automated basis-set superposition error (BSSE) calculation
Electron transfer analysis
Relaxed constraint algorithm (RCA) for converging SCF
G3Large basis set for transition metals
New MP2 options:
Dual-basis RIMP2 energy and analytical gradient
O2 energy and gradient
New wavefunction-based methods for efficiently calculating excited state properties:
SOS-CIS(D) energy for excited states
SOS-CIS(D0) energy and gradient for excited states
Coupled-cluster methods:
IP-CISD energy and gradient
EOM-IP-CCSD energy and gradient
OpenMP for parallel coupled-cluster calculations
QM/MM methods:
QM/MM full hessian evaluation
QM/MM mobile-block hessian (MBH) evaluation
Description for MM atoms with Gaussian-delocalized charge
Partial Hessian method for vibrational analysis
Faster correlated excited state method: RI-CIS(D) Potential energy surface crossing minimization with EOM-CCSD Dyson orbitals for ionization from the ground and excited states within CCSD and EOM-CCSD methods
It takes Q-Chem 8 minutes to do an energy and gradient calculation for this 103-atom taxol molecule at BLYP/6-311G (df,pd) level with 2000 basis functions on an 8-cpu opteron cluster.
MP2 at HF Speed
Highly efficient resolution-of-the-identity (RI) algorithms make medium & large basis MP2 calculations much more efficient, as shown in this example of computing the relative conformational energy of alanine
tetrapeptide (there are 27 low-lying structures!).
Linear-Scaling NMR Calculation
This diagram and table show the convergence of NMR shifts of the depicted object (N-methyl nicotinamide surrounded by hundreds of water molecules) versus the number of surrounding water molecules. They represent the largest NMR calculations, with up to 9000 basis functions at HF/6-31G** level.
A New Finding
Q-Chem’s unique EOM-SF-CCSD method, which is capable of efficiently describing multiple states of di- and tri-radicals, was used to discover the first example of an organic molecule with an open-shell doublet ground state. These three unpaired electrons are coupled antiferromagnetically in the DMX triradical.
