Chen Kuo-Mei
Department of Chemistry, National Sun Yat-sen University, Kaohsiung 804, Taiwan, Republic of China.
J Chem Phys. 2007 Jun 7;126(21):214307. doi: 10.1063/1.2734972.
A quantum treatment on ICN photodissociation from an initial perpendicular transition (Omega'=+/-1<--Omega"=0) to the asymptote CN(|Sigma+,J'M'N'1/2>)+I(2P3/2) is presented. Density matrices of both photofragments are derived and explicit expressions of the state multipoles in terms of the angular momentum coupling coefficients and the rotation-bending factors have been obtained. To perceive the physical origin of electronic angular momentum polarizations of the iodine photofragments, a correlation scheme which considers the magnetic dipolar and the electrostatic dipole-quadrupole interactions between I and CN cofragments is proposed. For ICN precursors in the vibrational ground state or in the equally populated l-type split levels, the alignment parameters of the iodine photofragments in the molecular frame can be calculated according to this long-range interaction model. For the perpendicular transition |1Pi1><--|1Sigma0+>, its alignment parameters of I(2P3/2) from the incoherent and coherent transitions to the |Omega'=1> and |Omega'=-1> components are rho(0)2(1Pi1)=0.756 and rho2(2)(1Pi1)=-0.656, respectively. For the perpendicular transition to |3Pi1>, rho(0)2(3Pi1)=-0.878 and rho2(2)(3Pi1)=0.328 are from the incoherent transition, whereas rho(0)2(3Pi1)=0.122 and rho2(2)(3Pi1)=0.328 are from the coherent transition. To analyze the photoion images of iodine photofragments, angular distributions of I+ from the 2+1 resonance-enhanced multiphoton ionization detection scheme are derived.
本文给出了对ICN光解离的量子处理，该光解离过程从初始的垂直跃迁（Ω′ = ±1 ← Ω″ = 0）到渐近态CN(|Σ⁺,J′M′N′1/2>) + I(2P3/2)。推导了两个光解离碎片的密度矩阵，并得到了用角动量耦合系数和转动弯曲因子表示的态多极矩的显式表达式。为了理解碘光解离碎片电子角动量极化的物理起源，提出了一种考虑I和CN共碎片之间磁偶极和静电偶极 - 四极相互作用的关联方案。对于处于振动基态或等布居l型分裂能级的ICN前体，可根据这种长程相互作用模型计算分子坐标系中碘光解离碎片的取向参数。对于垂直跃迁|1Pi1> ← |1Σ0⁺>，从非相干和相干跃迁到|Ω′ = 1>和|Ω′ = -1>分量的I(2P3/2)的取向参数分别为ρ(0)2(1Pi1) = 0.756和ρ2(2)(1Pi1) = -0.656。对于到|3Pi1>的垂直跃迁，来自非相干跃迁的ρ(0)2(3Pi1) = -0.878和ρ2(2)(3Pi1) = 0.328，而来自相干跃迁的ρ(0)2(3Pi1) = 0.122和ρ2(2)(3Pi1) = 0.328。为了分析碘光解离碎片的光离子图像，推导了2 + 1共振增强多光子电离检测方案中I⁺的角分布。
