QUENCHING OF INTERCONVERSION TUNNELING - THE FREE HCL STRETCH FIRST OVERTONE OF (HCL)(2)

Cavity ringdown laser absorption Spectroscopy has been used to record spectra of ((HCl)-Cl-35)(2) and its Cl-substituted mixed dimers at the first overtone of the free hydrogen stretch (2 yl). The dimers were p roduced in pulsed planar supersonic expansions. Significant quenching of interconversion tunneling (i.e., which exchanges the roles of H-bon d donor and acceptor) has been observed. Thus, the (HCl)-Cl-35-(HCl)-C l-37 and (HCl)-Cl-37-(HCl)-Cl-35 heterodimers are distinguished in the 2v(1) eigenstates, which is not the case for the ground and HCl-stret ch fundamental eigenstates because of facile tunneling mixing. (C) 199 8 American Institute of Physics.