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Journal Articles

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

Kurosaki, Yuzuru; Yokoyama, Keiichi; Teranishi, Yoshiaki

Chemical Physics, 308(3), p.325 - 334, 2005/01

https://doi.org/10.1016/j.chemphys.2004.05.032

Times Cited Count：23 Percentile：59.83(Chemistry, Physical)

A total of 1200 trajectories have been integrated for the two dissociation channels of formic acid, HCOOH H $_{2}$ O + CO (1) and HCOOH CO $_{2}$ + 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 H $_{2}$ O geometry in the TS of reaction 1 was predicted to significantly deviate from the equilibrium one, whereas the CO $_{2}$ 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.

Journal Articles

Photodissociation of acetaldehyde, CH $_{3}$ CHOCH $_{3}$ +HCO; Direct ab initio molecular dynamics study

Kurosaki, Yuzuru; Yokoyama, Keiichi

Chemical Physics Letters, 371(5-6), p.568 - 575, 2003/04

https://doi.org/10.1016/S0009-2614(03)00313-0

Times Cited Count：31 Percentile：68.97(Chemistry, Physical)

A total of 400 trajectories for the photodissociation, CH $_{3}$ CHOCH $_{3}$ +HCO, on the T $_{1}$ potential surface have been calculated using the direct ab initio molecular dynamics method at the UB3LYP/cc-pVDZ level of theory. It was predicted that the product CH $_{3}$ is neither vibrationally nor rotationally excited and HCO is vibrationally not excited but rotationally excited. The averaged HCO rotational energy was calculated to be 1.1 kcal/mol, which is 15.1 % of the available energy, 7.3 kcal/mol. The present result agrees with experiment within just a few percent of the observed data.

Journal Articles

Photodissociation of acetaldehyde, CH $_{3}$ CHOCH $_{4}$ +CO: Direct ab initio dynamics study

Kurosaki, Yuzuru; Yokoyama, Keiichi

Journal of Physical Chemistry A, 106(47), p.11415 - 11421, 2002/11

https://doi.org/10.1021/jp020998f

Times Cited Count：37 Percentile：73.47(Chemistry, Physical)

A total of 100 trajectories for the photodissociation, CH $_{3}$ CHO CH $_{4}$ + CO, on the S0 potential surface have been calculated using the direct ab initio molecular dynamics method at the RMP2(full)/cc-pVDZ level of theory. The energy distributions for the relative translational energy, the CO internal energy, and the CH $_{4}$ internal energy were calculated to be 28, 20, and 51 %, respectively. It was predicted that the product CO is highly rotationally excited but vibrationally almost not excited; on average, the rotational and vibrational quantum numbers were 68.2 and 0.15, respectively, which qualitatively agrees with the recent observation of Gherman et al. (J. Chem. Phys. 2001, 114, 6128.)

Journal Articles

Inner shell excitation and dissociation of condensed formamide

Ikeura, Hiromi*; Sekiguchi, Tetsuhiro; Kitajima, Yoshinori*; Baba, Yuji

Applied Surface Science, 169-170, p.282 - 286, 2001/01

https://doi.org/10.1016/S0169-4332(00)00671-1

Times Cited Count：8 Percentile：44.23(Chemistry, Physical)

Carbon and nitrogen K-shell excitation and dissociation of condensed formamide at 96 K were studied by near edge X-ray absorption fine structure (NEXAFS) recorded by total electron yield (TEY), total ion yield (TIY) and photon-stimulated desorption (PSD) yield of H+ measurements. It was found that electronic transitions from the C1s or the N1s to the *(C-H) and/or (N-H) enhanced ion yield of H+ from the C-H and/or N-H functional group. This selective dissociation indicates that the corresponding unoccupied molecular orbital has an antibonding character of the C-H and/or N-H. To investigate the molecular orientation of condensed formamide, incidence-angle-dependent TEY-NEXAFS spectra were measured. The CNO plane of the adsorbed formamide molecule is determined to be tilted away from the surface by an averaged angle of about 42 degrees.