The rovibrational spectrum of H-3(+) has been analyzed by taking into accou
nt that non-adiabatic couplings can be simulated by using atomic masses for
vibrational and nuclear masses for rotational motion. This results in comp
uted transition frequencies that reproduce experiment in most cases by a fa
ctor of 10 better than the original results including only adiabatic correc
tions. The deviation from experiment is in the range of a few hundredths of
a wavenumber. (C) 1999 Elsevier Science B.V. All rights reserved.