Selected resonance states of the deuterated formyl radical in the electronic ground state are computed using our recently introduced dynamically pruned discrete variable representation [H. R. Larsson, B. Hartke, and D. J. Tannor, J. Chem. Phys. 145, 204108 (2016)]. Their decay and asymptotic distributions are analyzed and, for selected resonances, compared to experimental results obtained by a combination of stimulated emission pumping and velocity-map imaging of the product D atoms. The theoretical results show good agreement with the experimental kinetic energy distributions. The intramolecular vibrational energy redistribution is analyzed and compared with previous results from an effective polyad Hamiltonian. Specifically, we analyzed the part of the wavefunction that remains in the interaction region during the decay. The results from the polyad Hamiltonian could mainly be confirmed. The C=O stretch quantum number is typically conserved, while the D—C=O bend quantum number decreases. Differences are due to strong anharmonic coupling such that all resonances have major contributions from several zero-order states. For some of the resonances, the coupling is so strong that no further zero-order states appear during the dynamics in the interaction region, even after propagating for 300 ps.
REFERENCES
To avoid unnecessary computational costs, not all the resonances have been propagated with the final parameters. Furthermore, the propagation for the filter diagonalization has been performed with a larger basis, but the results with the basis from Table I are virtually identical.
The PES of Ndengué et al. shows a better agreement to experimental data for many but not all resonances in HCO. Some wavenumbers and widths are actually still better described by the WKS surface. Thus, it cannot be expected that this PES would give much improved results than the two PESs studied here.
For (0, 4, 2), the resonance state computed with the SAG PES does show an IVR with a decrease in 3 to 2 and 1, but the initial state has a significant contribution near the linear configuration of DCO. Since linear configurations are not properly described (see text), this result has to be taken with caution.
