分子单重/叁重混合激发态碰撞传能中的量子干涉效应  

Quantum Interference Effect in Collision-induced Intramolecular Energy Transfer within Singlet-triplet Mixed States

作　　者：沙国河[1] 张存浩[1] 

机构地区：[1]中国科学院大连化学物理研究所分子反应动力学国家重点实验室,大连116023

出　　处：《物理化学学报》2004年第F08期1010-1016,共7页Acta Physico-Chimica Sinica

基　　金：国家重点基础研究发展规划项目(G1999075303)资助~~

摘　　要：量子干涉效应是基于量子力学波粒二象性原理,即微观粒子的运动皆具有波的特性而产生的一种干涉现象,故又称为物质波干涉.近年来,在分子的光激发、光解和光电离及碰撞过程中皆已观察到量子干涉效应,成为分子动态学领域研究热点之一.我们小组在国际上首次得到了单重/叁重混合激发态分子碰撞传能中的量子干涉的实验证据,从理论上导出了包括干涉相位角的传能截面公式,从实验上发展了激光双共振多光子电离光谱技术,用以测定了CO(A1Π,v=0/e3Σ-,v=1)与各种原子(He,Ne,Ar)及双原子分子H2,O2,N2,HCl碰撞传能的干涉角.其后又与李丽的小组合作,在热管炉中用激光双共振诱导荧光法观察到Na2(A1Σ+u,v=8/b3Π0u,v=14)-Na碰撞中的量子干涉效应,证明了碰撞干涉效应的普遍性.近年来,在理论方面,我们发展了基于含时微扰的一级波恩近似量子散射方法,计算出了上述碰撞体系的干涉角θST,与实验值符合极好.本文指出虽然气池实验测得的干涉角θST是不同分子碰撞速度及碰撞参数的“平均”结果,但与理论计算的微分干涉角尚比较接近,可提供激发态分子碰撞相互作用势的重要而难得的信息.The principle of wave-particle duality of quantum mechanics ascertains that any microscopic particle must also exhibit wave properties.T he matter wave,or de Broglie wave,wa s first evidenced by Davisson and Ger-mer in 1927in the electron diffraction by crystals.In recent years,nume rous fascinating examples of the quantum interference effect(QIE)have been discovered in the molecula r systems in their excitation,disso ciation and ion-ization by photons as well as in colli sion processes.Our group was the fir st to obtain the experimental eviden ce of QIE in a collision,specifically for the singlet-triplet mixed state of a diatomic species,and to derive an ex plicit ex-pression for its energy transfer cro ss-section.In this expression,the interference phase angle(θ ST )that describes the phase angle difference between s inglet and triplet energy transfer c hannels is defined and experimentally mea-sured for CO(A 1 Π,v=0/e 3 Σ - ,v=1)-M collision system with M =rare gase s(He,Ne,Ar ),homonuclear di-atomics(H 2 ,N 2 ,O 2 )and heteronuclear diatomics(HCl )via the optical-optical double resonance multiphoton ion-ization(OODR-MPI )technique.We have also observed QIE in Na 2 (A 1 Σ +u ,v=8/b 3 Π 0u ,v=14)-Na collision.More recently,we have carried out quantum scattering calculations of th e interference angle based on the fir st order Born approximation of time dependen t perturbation theory.For atom-dia tom collision,the anisotropic Lennard-Jones interaction potential was adopted,and for polar diatom-diatom collision,the long-range dipole-dipole interaction proportional to R -3 was shown to be a proper potential for the calculation.All the calcu-latedθ ST at T=77,253and 470K for CO(A 1 Π,v=0/e 3 Σ - ,v=1)-M,for M =He (θ ST =58°～65°),Ne (66°～69°),Ar (72°～90°)and HCl (101°～110°),are in good agreement with the experiments.Our calculated differen-tialθ ST are in the range of 48°�

关 键 词：单重-叁重混合态 碰撞传能 量子干涉 光学双共振多光子电离 

分 类 号：O641[理学—物理化学]