canonical variational transition-state theory (CVTST) 

https://doi.org/10.1351/goldbook.C00790
A development of transition-state theory in which the position of the dividing surface is varied so as to minimize the rate constant at a given temperature.
Source:
PAC, 1996, 68, 149. (A glossary of terms used in chemical kinetics, including reaction dynamics (IUPAC Recommendations 1996)) on page 155 [Terms] [Paper]