The quantitative determination of laser-induced molecular axis alignment

Area of Science:

• Physical Chemistry
• Molecular Dynamics
• Laser Spectroscopy

Background:

• Gas-phase experiments often average molecular dynamics, limiting detailed analysis.
• Laser alignment methods enable prealigning molecular axes for better insights.
• Transforming data to the molecular frame requires accurate axis alignment distributions, which are difficult to obtain.

Purpose of the Study:

• To present a general maximum-likelihood classification procedure for analyzing non-adiabatic numerical alignment simulations.
• To determine the most probable molecular frame angular dependence of a probe and the most likely laboratory frame axis alignment distribution.
• To provide confidence intervals for the determined distributions.

Main Methods:

• A maximum-likelihood classification procedure is described for non-adiabatic simulations.
• The method utilizes experimental data from an alignment-dependent probe.
• It involves analyzing free parameters in numerical alignment simulations.

Main Results:

• The procedure yields the most probable molecular frame angular dependence of the probe.
• It also determines the most likely laboratory frame axis alignment distribution.
• Confidence intervals are provided for both determined distributions.

Conclusions:

• The developed maximum-likelihood method accurately quantifies molecular alignment distributions.
• This approach enhances the study of molecular dynamics by enabling frame transformations.
• It is applicable to complex polyatomic molecules and provides reliable quantitative data.