Bryukov Mikhail G, Dellinger Barry, Knyazev Vadim D
Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, USA.
J Phys Chem A. 2006 Jul 27;110(29):9169-74. doi: 10.1021/jp061038m.
An experimental, temperature-dependent kinetic study of the gas-phase reaction of the hydroxyl radical with molecular bromine (reaction 1) has been performed by using a pulsed laser photolysis/pulsed-laser-induced fluorescence technique over a wide temperature range of 297-766 K, and at pressures between 6.68 and 40.29 kPa of helium. The experimental rate coefficients for reaction 1 demonstrate no correlation with pressure and exhibit a negative temperature dependence with a slight negative curvature in the Arrhenius plot. A nonlinear least-squares fit with two floating parameters of the temperature-dependent k(1)(T) data set using an equation of the form k(1)(T) = AT(n) yields the recommended expression k(1)(T) = (1.85 x 10(-9))T(-0.66) cm(3) molecule(-1) s(-1) for the temperature dependence of the reaction 1 rate coefficient. The potential energy surface (PES) of reaction 1 was investigated with use of quantum chemistry methods. The reaction proceeds through formation of a weakly bound OH...Br(2) complex and a PES saddle point with an energy below that of the reactants. Temperature dependence of the reaction rate coefficient was modeled by using the RRKM method on the basis of the calculated PES.
利用脉冲激光光解/脉冲激光诱导荧光技术，在297 - 766 K的宽温度范围以及6.68至40.29 kPa氦气压力下，对羟基自由基与分子溴的气相反应（反应1）进行了与温度相关的实验动力学研究。反应1的实验速率系数与压力无关，在Arrhenius图中呈现负温度依赖性且有轻微负曲率。使用形式为k(1)(T) = AT(n)的方程对与温度相关的k(1)(T)数据集进行具有两个浮动参数的非线性最小二乘拟合，得出反应1速率系数温度依赖性的推荐表达式k(1)(T) = (1.85 x 10(-9))T(-0.66) cm(3) molecule(-1) s(-1)。利用量子化学方法研究了反应1的势能面（PES）。该反应通过形成弱束缚的OH...Br(2)络合物和一个能量低于反应物的PES鞍点进行。基于计算得到的PES，使用RRKM方法对反应速率系数的温度依赖性进行了建模。
