OH（2π(3/2)，J = 3/2，f）与HCl进行态-态散射中的立体效应。

Steric effects in state-to-state scattering of OH (2pi(3/2),J=3/2,f) by HCl.

作者信息

Cireasa R, Moise A, ter Meulen J J

机构信息

Applied Molecular Physics, Institute for Molecules and Materials, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands.

出版信息

J Chem Phys. 2005 Aug 8;123(6):64310. doi: 10.1063/1.1978874.

DOI:10.1063/1.1978874

PMID:16122311

Abstract

In this paper we address stereo-dynamical issues in the inelastic encounters between OH (chi2pi) radicals and HCl (chi1sigma+). The experiments were performed in a crossed molecular-beam machine at the nominal collision energy of 920 cm(-1). Prior to the collisions, the OH molecules were selected using a hexapole in a well-defined rotational state v=0, omega=32, J=32, M(J)=32, f, and subsequently oriented in a homogeneous electrical field. We have measured rotationally resolved relative cross sections for collisions in which OH is oriented with either the O side or the H side towards HCl, from which we have calculated the corresponding steric asymmetry factors S. The results are presented in comparison with data previously obtained by our group for the inelastic scattering of OH by CO (E(coll)=985 cm(-1)) and N2 (E(coll)=985 cm(-1)) studied under similar experimental conditions. The dissimilarity in the behavior of the OH+HCl system revealed by this comparison is explained on the basis of the difference in the anisotropy of the interaction potential governing the collisions. The interpretation of the data takes into account the specific features of both nonreactive and reactive parts of the potential-energy surface. The results indicate that the scattering dynamics at this collision energy may be influenced by the HO-HCl van der Waals well and by reorientation effects determined by the long-range electrostatic forces and, furthermore, may involve reactive collisions.

摘要

在本文中，我们探讨了OH（χ²π）自由基与HCl（χ¹σ⁺）之间非弹性碰撞中的立体动力学问题。实验是在交叉分子束装置中以920 cm⁻¹的标称碰撞能量进行的。在碰撞之前，使用六极杆将OH分子选择为处于明确的转动状态v = 0、ω = 32、J = 32、M（J） = 32、f，随后在均匀电场中使其取向。我们测量了OH以O侧或H侧朝向HCl的碰撞的转动分辨相对截面，由此计算出了相应的空间不对称因子S。将结果与我们小组先前在类似实验条件下对OH与CO（E（coll） = 985 cm⁻¹）和N₂（E（coll） = 985 cm⁻¹）的非弹性散射所获得的数据进行了比较。基于控制碰撞的相互作用势的各向异性差异，解释了这种比较所揭示的OH + HCl系统行为的差异。对数据的解释考虑了势能面的非反应部分和反应部分的具体特征。结果表明，在此碰撞能量下的散射动力学可能受到HO - HCl范德华势阱以及由长程静电力决定的重新取向效应的影响，此外，可能还涉及反应性碰撞。