Threshold behavior in metastable dissociation of multi-photon ionized thymine and uracil
Threshold behavior in metastable dissociation of multi-photon ionized thymine and uracil
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DOI：
10.1016/j.cplett.2017.06.051
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发表时间：
2017-09-16
影响因子：
2.8
通讯作者：
Eden, S.
中科院分区：
文献类型：
--
作者：
Pandey, R.;Ryszka, M.;Eden, S.
已经从气相中的单色多光子电离的嘧啶核碱基观察到微秒时间尺度的HNCO损失。亚稳态通道的光子能量阈值已被测量为5.55 +/- 0.02 eV的胸腺嘧啶和5.57 +/- 0.02 eV的尿嘧啶。我们认为，这些结果可以归因于访问分子的S-1状态与额外的振动能量匹配的阈值能量从自由基阳离子的HNCO损失。结合先前的光电离能，这使得能够推导出Si绝热能量：胸腺嘧啶为3.67 +/- 0.07 eV，尿嘧啶为3.77 +/- 0.07 eV。这些值与最近的计算一致。(C)2017爱思唯尔B. V.保留所有权利。
Microsecond-timescale HNCO loss has been observed from single-color multi-photon ionized pyrimidine nucleobases in the gas phase. Photon energy thresholds for the metastable channels have been measured at 5.55 +/- 0.02 eV for thymine and 5.57 +/- 0.02 eV for uracil. We argue that these results can be attributed to accessing the molecules' S-1 states with additional vibrational energy matching the threshold energy for HNCO loss from the radical cation. Combined with previous photoionization energies, this enables the Si adiabatic energies to be deduced: 3.67 +/- 0.07 eV for thymine and 3.77 +/- 0.07 eV for uracil. These values are consistent with recent calculations. (C) 2017 Elsevier B.V. All rights reserved.