Direct ab initio molecular dynamics study of the two photodissociation channels of formic acid

作者：Kurosaki Y^*; Yokoyama K; Teranishi Y

来源：Chemical Physics, 2005, 308(3): 325-334.

DOI：10.1016/j.chemphys.2004.05.032

A total of similar to1200 trajectories have been integrated for the two photodissociation channels of formic acid, HCOOH --> H2O + CO (1) and HCOOH --> CO2 + H-2 (2), which occur with 248 and 193 nm photons, using the direct ab initio molecular dynamics method at the RMP2(full)/cc-pVDZ level of theory. It was found that the percentage of the energy distributed to a relative translational mode in reaction (2) is much larger than that in reaction (1). This is mainly due to the difference in the geometry of transition state (TS); the H2O geometry in the TS of reaction (1) was predicted to significantly deviate from the equilibrium one, whereas the CO2 and H-2 geometries in the TS of reaction (2) were found to be more similar to their equilibrium ones. It was also found that the product diatomic molecules, CO and H-2, are both vibrationally and rotationally excited. The calculated relative population of the vibrationally excited CO for the 248 nm photodissociation was consistent with experiment.

• 出版日期2005-1-31