Electronic angular momentum polarizations of photofragments: A case study of ICN photodissociation from a perpendicular transition

摘要

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(P-2(3/2)) 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 (1)Pi(1)><-(1)Sigma(+)(0)>, its alignment parameters of I(P-2(3/2)) from the incoherent and coherent transitions to the Omega'=1 > and Omega'=-1 > components are rho(2)(0)((1)Pi(1))=0.756 and rho(2)(2)((1)Pi(1))=-0.656, respectively. For the perpendicular transition to (3)Pi(1)>, rho(2)(0)((3)Pi(1))=-0.878 and rho(2)(2)((3)Pi(1))=0.328 are from the incoherent transition, whereas rho(2)(0)((3)Pi(1))=0.122 and rho(2)(2)((3)Pi(1))=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. (c) 2007 American Institute of Physics.