This is the nonadiabatic statistical theory (NAST) package for predicting kinetics of spin-dependent processes, including intersystem crossings, spin-forbidden reactions, and spin crossovers. The NAST package can calculate the probabilities and rates of transitions between the electronic states of different spin multiplicities. Both the microcanonical (energy dependent) and canonical (temperature dependent) rate constants can be obtained. Quantum effects, including tunneling, zero-point vibrational energy, and reaction path interference can be accounted for. In the limit of an adiabatic reaction proceeding on a single electronic state, NAST reduces to the traditional transition state theory.

If you use the NAST package, please site the following publications:

1. V.D. Dergachev, M. Rooein, I.D. Dergachev, A.O. Lykhin, R.C. Mauban, S.A. Varganov, NAST: Nonadiabatic Statistical Theory Package for Predicting Kinetics of Spin‐Dependent Processes. Topics in Current Chemistry 2022, 380, 15. https://rdcu.be/cHISz

2. Lykhin, A. O.; Kaliakin, D. S.; DePolo, G. E.; Kuzubov, A. A.; Varganov, S. A. Nonadiabatic Transition State Theory: Application to Intersystem Crossings in the Active Sites of Metal-Sulfur Proteins. Int. J. Quantum Chem. 2016, 116 (10), 750–761. https://doi.org/10.1002/qua.25124.