nonadiabatic coupling

https://doi.org/10.1351/goldbook.N04180
This is @M04007@ @C01025@ between two @A00141@ potential-energy surfaces.
See also:
adiabatic
Source:
PAC, 1996, 68, 149. (A glossary of terms used in chemical kinetics, including reaction dynamics (IUPAC Recommendations 1996)) on page 175 [Terms] [Paper]