Dissociation of H2NCH Dication in a Strong Laser Field

详细信息    查看全文

• 作者：Jia Zhou ; H. Bernhard Schlegel
• 刊名：Journal of Physical Chemistry A
• 出版年：2011
• 出版时间：August 4, 2011
• 年：2011
• 卷：115
• 期：30
• 页码：8375-8379
• 全文大小：774K
• 年卷期：v.115,no.30(August 4, 2011)
• ISSN：1520-5215

文摘

Ab initio classical molecular dynamics calculations have been used to simulate the dissociation of H₂NCH²⁺ in a strong laser field. The frequencies of the continuous oscillating electric field were chosen to be 蠅 = 0.02, 0.06, and 0.18 au (2280, 760, and 253 nm, respectively). The field had a maximum strength of 0.03 au (3.2 脳 10¹³ W cm^鈥?) and was aligned with the CN bond. Trajectories were started with 100 kcal/mol of vibrational energy above zero point and were integrated for up to 600 fs at the B3LYP/6-311G(d,p) level of theory. A total of 200 trajectories were calculated for each of the three different frequencies and without a field. Two dissociation channels are observed: HNCH⁺ + H⁺ and H₂NC⁺ + H⁺. About one-half to two-thirds of the H⁺ dissociations occurred directly, while the remaining indirect dissociations occurred at a slower rate with extensive migration of H⁺ between C and N. The laser field increased the initial dissociation rate by a factor of ca. 1.4 and decreased the half-life by a factor of ca. 0.75. The effects were similar at each of the three frequencies. The HNCH⁺ to H₂NC⁺ branching ratio decreased from 10.6:1 in the absence of the field to an average of 8.4:1 in the laser field. The changes in the rates and branching ratios can be attributed to the laser field lowering the reaction barriers as a result of a difference in polarizability of the reactant and transition states.