Photofragment angular momentum distributions from oriented and aligned polyatomic molecules: beyond the axial recoil limit

Abstract

A semi-classical theoretical treatment is presented for the description of photofragment polarization in the molecular frame, from the non-axial photodissociation of molecules which are oriented in the laboratory frame. Explicit expressions which quantify the experimental sensitivity to each of the polarization parameters, for prompt photodissociation, are given in terms of the non-axial-recoil deflection angles χ, α and ϕ_μd (which describe the orientation of the dipole and transition dipole moments about the recoil velocity), and the degree of the parent orientation and alignment. The application of this approach for the extraction of important dynamical information in the molecular frame is discussed, including cases where this information cannot be measured for isotropic samples of parent molecules.

Keywords:

• photodissociation
• polarization
• photofragment alignment

Acknowledgements

This research has been financially supported by the councils for Chemical Sciences and Physical Sciences of the Dutch Organization for Scientific Research (NWO-CW, NWO-FOM). TPR thanks the EU for support to access the facilities of the Laser Centre Vrije Universiteit for which funding was received from the EC's Seventh Framework Programme (FP7/2007-2013) under grant agreement n° 228334, and for support through the European Research Council grant “TRICEPS” (GA No. 207542). The authors would like to acknowledge further support through the EU-Marie Curie ITN Programme ICONIC (PITN-GA-2009-238671). Finally, the authors thank Dick Zare for his pioneering achievements and inspirational vision in the field of reaction dynamics; moreover we are grateful both for his mentoring and friendship.