Mv. Vener et Nd. Sokolov, ON THE ADIABATIC SEPARATION OF THE VIBRATIONAL VARIABLES OF A HYDROGEN-BONDED AHA FRAGMENT WITH A SYMMETRICAL DOUBLE-WELL POTENTIAL, Chemical physics letters, 264(3-4), 1997, pp. 429-434
The adiabatic separation of the vibrational variables of a hydrogen-bo
nded AHA fragment with a symmetric double-well potential is considered
using two approaches. In the first approach the A...A stretch vibrati
on is slow in comparison to the proton vibration. It is applicable to
the energy level calculations of an AHA fragment with a potential barr
ier of arbitrary height. In the alternative approach the proton is con
sidered to be a ''slow'' subsystem. This approach appears to be of lim
ited applicability. For an AHA fragment with a symmetric double-well p
otential the Born-Oppenheimer criterion is shown to contain the freque
ncy corresponding to the proton 0 --> 2 transition in both approaches.