検索対象:     
報告書番号:
※ 半角英数字
 年 ~ 
 年

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

ギ酸の二つの解離反応についてのdirect ab initio molecular dynamics計算

黒崎 譲; 横山 啓一; 寺西 慶哲

Kurosaki, Yuzuru; Yokoyama, Keiichi; Teranishi, Yoshiaki

248及び193nmの光によるギ酸の二つの解離反応、HCOOH$$rightarrow$$H$$_{2}$$O+CO(1)及びHCOOH$$rightarrow$$CO$$_{2}$$+H$$_{2}$$(2)、について、RMP2(full)/cc-pVDZレベルでのdirect ab initio molecular dynamics法を用いて約1200本の古典トラジェクトリを計算した。その結果、反応2における相対並進モードへのエネルギー分配の割合は、反応1におけるそれよりもはるかに大きいことが明らかとなった。このことは反応1と2の遷移状態の構造の違いによるところが大きいと考えられる。また、生成物であるCOとH$$_{2}$$はともに振動,回転状態が励起されていることが予測された。本計算から見積もられたCOの振動状態分布は、248nm光による光解離実験の値とよく一致した。

A total of $$sim$$ 1200 trajectories have been integrated for the two dissociation channels of formic acid, HCOOH $$rightarrow$$ H$$_{2}$$O + CO (1) and HCOOH $$rightarrow$$ 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.

Access

:

- Accesses

InCites™

:

パーセンタイル:39.72

分野:Chemistry, Physical

Altmetrics

:

[CLARIVATE ANALYTICS], [WEB OF SCIENCE], [HIGHLY CITED PAPER & CUP LOGO] and [HOT PAPER & FIRE LOGO] are trademarks of Clarivate Analytics, and/or its affiliated company or companies, and used herein by permission and/or license.