Ionization-induced Long-lasting Orientation of Symmetric-top Molecules

TL;DR

This paper theoretically investigates how two-color laser pulses can induce long-lasting, field-free orientation in symmetric-top molecules through anisotropic ionization, with potential applications in molecular control and spectroscopy.

Contribution

It introduces a theoretical model showing how anisotropic ionization leads to persistent molecular orientation, enhanced by multiple pulses and affected by temperature.

Findings

Orientation increases with laser intensity and temperature.

Multiple delayed pulses further enhance orientation.

Probing methods include harmonic generation and Coulomb explosion.

Abstract

We theoretically consider the phenomenon of field-free long-lasting orientation of symmetric-top molecules ionized by two-color laser pulses. The anisotropic ionization produces a significant long-lasting orientation of the surviving neutral molecules. The degree of orientation increases with both the pulse intensity and, counterintuitively, with the rotational temperature. The orientation may be enhanced even further by using multiple delayed two-color pulses. The long-lasting orientation may be probed by even harmonic generation or by Coulomb-explosion-based methods. The effect may enable the study of relaxation processes in dense molecular gases, and may be useful for molecular guiding and trapping by inhomogeneous fields.