Resonant four-wave mixing spectra: A fresh look at photodissociation dynamics

22nd International Conference on Spectral Line Shapes

Kouzov, A.^1 ; Radi, P.^2 ; Maksyutenko, P.^2 ; Kozlov, D.^3

Saint-Petersburg State University, Saint-Petersburg

198504, Russia^1

Paul Scherrer Insitute, Villigen

5232, Switzerland^2

A.M. Prokhorov General Physics Institute, Moscow

119991, Russia^3

关键词: Characteristic shapes;    Flexible polarizations;    Key characteristics;    Photodissociation dynamics;    Polarization factor;    Recoil velocities;    Resonance amplitudes;    Rotational anisotropy;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/548/1/012016/pdf
DOI  :  10.1088/1742-6596/548/1/012016

来源: IOP

【 摘 要 】

Frequency- and polarization-resolved degenerate resonant four-wave mixing is used for the first time to study the rotational anisotropy of the OH radicals produced by photolysis of H2O2by a plane-polarized laser radiation at 266 nm. For that, a flexible polarization setup is designed to directly isolate the rotationally anisotropic signals in the A2Σ+-X2Π(0, 0) OH vibronic band. The results are quantitatively interpreted by using the line-space approach and accounting for all possible correlations between the electric field EDof the photolysis laser, the recoil velocity v and the angular momentum J of nascent particles. In so doing, the resonance amplitudes are decoupled into products of the polarization factors, the Doppler-broadened profiles and the Einstein B-coefficients. The anisotropic signals have characteristic shapes of well resolved Doppler doublets providing a direct evidence of translational helicity of the nascent OH radicals, a hitherto exprementally inaccessible key characteristic of the photodissociation path.