MICROWAVE ROTATIONAL SPECTRUM OF GAUCHE ETHYL-ALCOHOL IN EXCITED-STATES OF THE -OH TORSION

The microwave rotational spectrum of gauche CH3CH2OH has been identifi ed and assigned for the two substates of the first excited state of th e -OH torsion. Since mu(b) similar or equal to 0 by accident, only a-d ipole transitions have been assigned. It was not possible to observe t he c-dipole transitions since the tunneling frequency between the two substates is expected to be on the order of 1.7 THz. The assigned line s do not give a rigid rotor fit. The spectrum has been calculated usin g the IAM program of Liu for asymmetric-asymmetric molecules, which wa s of little use in the analysis. However, it has been necessary to det ermine improved potential energy coefficients for the -OH torsion with the result V-1 = 45.3 cm(-1), V-2 = 13.0 cm(-1), and V-3 = 370.0 cm(- 1). (C) 1996 Academic Press, Inc.