电子与SF5X化合物的附着：SF5C6H5、SF5C2H3、S2F10和SF5Br，温度范围为300 - 550K。

Electron attachment to SF5X compounds: SF5C6H5, SF5C2H3, S2F10, and SF5Br, 300-550 K.

作者信息

Miller Thomas M, Viggiano A A, Dolbier William R, Sergeeva Tatiana A, Friedman Jeffrey F

机构信息

Air Force Research Laboratory, Space Vehicles Directorate, Hanscom Air Force Base, Bedford, Massachusetts 01731-3010, USA.

出版信息

J Phys Chem A. 2007 Feb 15;111(6):1024-9. doi: 10.1021/jp066656h.

DOI:10.1021/jp066656h

PMID:17286358

Abstract

Rate constants and ion product channels have been measured for electron attachment to four SF5 compounds, SF5C6H5, SF5C2H3, S2F10, and SF5Br, and these data are compared to earlier results for SF6, SF5Cl, and SF5CF3. The present rate constants range over a factor of 600 in magnitude. Rate constants measured in this work at 300 K are 9.9+/-3.0x10(-8) (SF5C6H5), 7.3+/-1.8x10(-9) (SF5C2H3), 6.5+/-2.5x10(-10) (S2F10), and 3.8+/-2.0x10(-10) (SF5Br), all in cm3 s-1 units. SF5- was the sole ionic product observed for 300-550 K, though in the case of S2F10 it cannot be ascertained whether the minor SF4- and SF6- products observed in the mass spectra are due to attachment to S2F10 or to impurities. G3(MP2) electronic structure calculations (G2 for SF5Br) have been carried out for the neutrals and anions of these species, primarily to determine electron affinities and the energetics of possible attachment reaction channels. Electron affinities were calculated to be 0.88 (SF5C6H5), 0.70 (SF5C2H3), 2.95 (S2F10), and 2.73 eV (SF5Br). An anticorrelation is found for the Arrhenius A-factor with exothermicity for SF5- production for the seven molecules listed above. The Arrhenius activation energy was found to be anticorrelated with the bond strength of the parent ion.

摘要

已测量了电子附着到四种SF5化合物（SF5C6H5、SF5C2H3、S2F10和SF5Br）上的速率常数和离子产物通道，并将这些数据与早期关于SF6、SF5Cl和SF5CF3的结果进行了比较。目前的速率常数在数量级上相差600倍。在这项工作中于300 K测量的速率常数分别为9.9±3.0×10(-8)（SF5C6H5）、7.3±1.8×10(-9)（SF5C2H3）、6.5±2.5×10(-10)（S2F10）和3.8±2.0×10(-10)（SF5Br），单位均为cm3 s-1。在300 - 550 K时，SF5-是唯一观察到的离子产物，不过对于S2F10，无法确定质谱中观察到的少量SF4-和SF6-产物是由于附着到S2F10上还是由于杂质。已对这些物种的中性分子和阴离子进行了G3(MP2)电子结构计算（对于SF5Br为G2），主要是为了确定电子亲和能以及可能的附着反应通道的能量学。计算得出的电子亲和能分别为0.88（SF5C6H5）、0.70（SF5C2H3）、2.95（S2F10）和2.73 eV（SF5Br）。对于上述七种分子生成SF5-的反应，发现阿仑尼乌斯A因子与放热性呈反相关。发现阿仑尼乌斯活化能与母体离子的键强呈反相关。