Mechanism of Cis-to-Trans Isomerization of Azobenzene: Direct MD Study
Mechanism of Cis-to-Trans Isomerization of Azobenzene: Direct MD Study
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DOI：
10.1021/jp027707n
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发表时间：
2003-05
影响因子：
2.9
通讯作者：
T. Ikegami;N. Kurita;A. Sekino;Y. Ishikawa
中科院分区：
文献类型：
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作者：
T. Ikegami;N. Kurita;A. Sekino;Y. Ishikawa
用直接分子动力学方法研究了顺式偶氮苯热异构化反应。采用半经验PM3方法计算了力场，并通过密度泛函（PW91）计算进行了验证。用这两种方法寻找了反应的过渡态。轨迹从过渡态开始，用零点振动进行修饰，并收集瞬态振动谱。发现在1 ps处激发出两种类型的振动模式，这两种模式都对应于苯环的面内骨架振动（ν8和ν19）。这些模式的寿命估计分别为1.2和1.8 ps。结果表明，苯环的ν8和ν19模在热异构化反应中起重要作用。
The thermal isomerization reaction of cis-azobenzene to its trans isomer has been studied by direct molecular dynamics. The semiempirical PM3 method was used to calculate the force field, which was verified by density functional (PW91) calculations. The transition state for the reaction was searched by both methods. The trajectories were started from the transition state dressed with zero-point vibration, and the transient vibrational spectrum was collected. Two types of the vibrational modes were found to be excited at 1 ps, both of which correspond to in-plane skeletal vibration of the benzene ring (ν8 and ν19). The lifetimes of those modes are estimated to be 1.2 and 1.8 ps, respectively. The results indicate that ν8 and ν19 modes of the benzene ring play an important role in the thermal isomerization.