Single-seat license is designed to be used on a single standalone workstation with up to 32 cores.
Cluster license is intended to be used on smaller clusters with up to 256 cores (so on a cluster with 16 cores per node, Q-Chem could be licensed on up to 16 nodes).
Unlimited license is best suited for larger computer clusters or a larger number of individual workstations.
Single Research Group: Research under the supervision of a single principal investigator
Multi-Group License: Multiple academic research groups
Site License: All research groups on a single site
Include BrianQC module for NVIDIA GPU computing
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Q-Chem is an ab initio quantum chemistry software package for fast and accurate simulations of molecular systems, including electronic and molecular structure, reactivities, properties, and structure.
New Features in Q-Chem 6.4
Q-Chem 6.4 is here! Upgrade and enjoy improved performance and usability, as well as new tools for studying chemistry and spectroscopy. With these new features, you can deploy large-scale calculations and workflows, get more accurate results faster, and extend the scope of your research to include systems and research questions that were not previously accessible.
Spectroscopy modeling:
Core-valence separation (CVS) scheme for ROCIS, XCIS, and QROCIS: Calculate accurate core-level spectra of open-shell systems Avik Ojha, John Herbert
Inner-valence projection option for EOM-IP/EE-CCSD solvers: Calculate high-lying excited/ionized states dominated by the removal of an inner-valence electron by using a CVS-like treatment. Wojtek Skomorowski
New ¥ÄSCF Driver: Run ¥ÄSCF calculations easier and more quickly, with a streamlined, simple interface and new useful tools for analysis of results Juanes Arias Martinez
Performance improvements and features for large systems:
Iterative CC-in-DFT embedding approach for property calculations Anthuan Ferino Pérez, Thomas Jagau
A two-step Cholesky decomposition for CC/EOM-CC energy and gradient: Provides faster CD calculations, especially for gradient Tingting Zhao, Anna Krylov
Stochastic RI-CC2 analytical gradients and derivative coupling (Additional Publication) Chongxiao Zhao, Wenjie Dou, Chenyang Li, Joonho Lee, Qi Ou
Support for B97-type functionals in TAO-DFT Shaozhi Li, Jeng-Da Chai
PBEh-3c and HF-3c Seminumerical Analytic Frequency: Provides similar accuracy and scaling to analytic Hessians. HF-3c especially is good for very efficient geometry optimizations (good accuracy for noncovalent interactions at the cost of minimal-basis Hartree-Fock). Also includes frequencies! Avik Ojha, John Herbert
Upgrade to DFT-D4
Mixed-reference SF-DFT (MR-SF-DFT): Improves accuracy and solves the spin-contamination problem in the original SF-TD-DFT Arnab Chakraborty, Zheng Pei, Yihan Shao, Anna Krylov
NEO developments:
NEO-CC2 method for excited states Jonathan Fetherolf, Sharon Hammes-Schiffer
NEO-CCSD(T) and NEO-CCSDTeep,epp methods Rowan Goudy, Sharon Hammes-Schiffer
Frozen core approximation for NEO methods Rowan Goudy, Sharon Hammes-Schiffer
Geometry optimization with finite-difference gradients for NEO-CC Rowan Goudy, Sharon Hammes-Schiffer