Miller Thomas M, Viggiano A A, Friedman Jeffrey F, Van Doren Jane M
Air Force Research Laboratory, Space Vehicles Directorate, Hanscom Air Force Base, Bedford, Massachusetts 01731-3010, USA.
J Chem Phys. 2004 Nov 22;121(20):9993-8. doi: 10.1063/1.1806418.
Rate constants for electron attachment to the three isomers of trifluoromethylbenzonitrile [(CF(3))(CN)C(6)H(4), or TFMBN] were measured over the temperature range of 303-463 K in a 133-Pa He buffer gas, using a flowing-afterglow Langmuir-probe apparatus. At 303 K, the measured attachment rate constants are 9.0 x 10(-8) (o-TFMBN), 5.5 x 10(-8) (m-TFMBN), and 8.9 x 10(-8) cm(3) s(-1) (p-TFMBN), estimated accurate to +/-25%. The attachment process formed only the parent anion in all three cases. Thermal electron detachment was observed for all three anion isomers, and rate constants for this reverse process were also measured. From the attachment and detachment results, the electron affinities of the three isomers of TFMBN were determined to be 0.70(o-TFMBN), 0.67(m-TFMBN), and 0.83 eV (p-TFMBN), all +/-0.05 eV. G3(MP2) [Gaussian-3 calculations with reduced Møller-Plesset orders (MP2)] calculations were carried out for the neutrals and anions. Electron affinities derived from these calculations are in good agreement with the experimental values.
在133帕的氦缓冲气体中，使用流动余辉朗缪尔探针装置，在303 - 463 K的温度范围内测量了电子与三氟甲基苯甲腈的三种异构体[（CF(3))(CN)C(6)H(4)，即TFMBN]的附着速率常数。在303 K时，测得的附着速率常数分别为9.0×10(-8)（邻位TFMBN）、5.5×10(-8)（间位TFMBN）和8.9×10(-8) cm(3) s(-1)（对位TFMBN），估计精度为±25%。在所有三种情况下，附着过程仅形成母体阴离子。观察到所有三种阴离子异构体的热电子脱离，并测量了该逆过程的速率常数。根据附着和脱离结果，确定TFMBN的三种异构体的电子亲和能分别为0.70（邻位TFMBN）、0.67（间位TFMBN）和0.83 eV（对位TFMBN），均为±0.05 eV。对中性分子和阴离子进行了G3(MP2) [具有简化的莫勒-普莱塞阶数（MP2）的高斯-3计算]。从这些计算得出的电子亲和能与实验值吻合良好。
