Semiclassical transition state theory

Semiclassical Transition State Theory (SCTST)^[1][2] is an efficient chemical rate theory, which aims to calculate accurate rate constants of chemical reactions, including nuclear quantum effects such as tunnelling, from ab initio quantum chemistry.^[3][4][5] The method makes use of the semiclassical WKB wavefunction, Bohr-sommerfeld theory and vibrational perturbation theory to derive an analytical relation for the probability of a particle transmitting through a potential barrier at some energy, E. It was first developed by Bill Miller and coworkers in the 1970's, and has been further developed to allow for application to larger systems^[6] and using more accurate potentials.^[7]