Unimolecular dissociation dynamics of highly vibrationally excited DCO(X 2A). II. Calculation of resonance energies and widths and comparison with high-resolution spectroscopic data

Abstract

We present a theoretical study of the unimolecular dissociation of DCO in the electronic ground state, X̃ 1A, using a new ab initio potential energy surface. Altogether we have analyzed about 140 resonances up to an energy of ≈1.4 eV above the D+CO threshold, corresponding to the ninth overtone in the CO stretching mode (v2=9). The agreement of the resonance positions and widths with recent stimulated emission pumping measurements of Stöck et al. [J. Chem. Phys. 106, 5333 (1997), the preceding article] is pleasing. The root-mean-square deviation from the experimental energies is only 16 cm−1 over a range of about 16 500 cm−1 and all trends of the resonance widths observed in the experiment are satisfactorily reproduced by the calculations. A strong 1:1:2 stretch–stretch–bend resonance prohibits a unique assignment for the majority of vibrational states.