Rovibrational energy levels of H3+ with energies above the barrier to linearity

The H-3(+) potential energy surface is sampled at 5900 geometries with the emphasis on the nonequilibrium and asymptotic points. Apart from the Born-Oppenheimer energy converged to the accuracy better than 0.02 cm(-1), the adiabatic and the leading relativistic corrections are computed at each geometry. To represent analytically the potential energy surface, the parameters of a power series are determined by fitting to the computed energy points. Possible choice of nuclear masses simulating the nonadiabatic effects in solving the nuclear Schrodinger equation is analyzed. A set of theoretically predicted rovibrational transitions is confronted with the experimental data in the 10 700-13 700 cm(-1) window of the spectra. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3167795]