New features in the Q-Chem 6.4 release include:
- Core-valence separation (CVS) scheme for ROCIS, XCIS, and QROCISfor calculating accurate core-level spectra of open-shell systems (Avik Ojha, John Herbert)
- New ΔSCF Driver provides a streamlined, simple interface for running ΔSCF calculations and useful tools for analysis of results (Juanes Arias Martinez)
- Mixed-reference SF-DFT (MR-SF-DFT) energies provide improved accuracy and solve the spin-contamination problem in the original SF-TD-DFT (Arnab Chakraborty, Zheng Pei, Yihan Shao, Anna Krylov)
- Iterative CC-in-DFT embedding provides accurate prediction of properties at reduced cost (Anthuan Ferino Pérez, Thomas Jagau)
- Faster CC/EOM-CC energy and gradient calculations via a two-step Cholesky decomposition (Tingting Zhao, Anna Krylov)
- Stochastic RI-CC2 analytical gradients and derivative coupling enables CC2 excited state calculations on much larger systems (Chongxiao Zhao, Wenjie Dou, Chenyang Li, Joonho Lee, Qi Ou)
- PBEh-3c and HF-3c seminumerical analytic frequency provides good accuracy and scaling (similar to analytic Hessians); HF-3c is particularly good for efficient geometry optimizations (Avik Ojha, John Herbert)
https://www.q-chem.com/explore/qc64