Asymptotic model for shape resonance control of diatomics by intense non-resonant light: Universality in the single-channel approximation

TL;DR

This paper develops an asymptotic model to describe how intense non-resonant light modifies shape resonances in diatomic molecules, revealing universal and approximately linear behavior in the field intensity, and introduces a perturbative single-channel approach for control.

Contribution

It introduces a universal asymptotic model combining nodal line technique and perturbation theory to efficiently predict shape resonance modifications under non-resonant light in diatomics.

Findings

Field-dressed shape resonances are approximately linear in intensity.

Universal dependence on the field-free scattering length.

Single-channel model agrees well with full multi-channel calculations.

Abstract

Non-resonant light interacting with diatomics via the polarizability anisotropy couples different rotational states and may lead to strong hybridization of the motion. The modification of shape resonances and low-energy scattering states due to this interaction can be fully captured by an asymptotic model, based on the long-range properties of the scattering [Crubellier et al. arXiv:1412.0569]. Remarkably, the properties of the field-dressed shape resonances in this asymptotic multi-channel description are found to be approximately linear in the field intensity up to fairly large intensity. This suggests a perturbative single-channel approach to be sufficient to study the control of such resonances by the non-resonant field. The multi-channel results furthermore indicate the dependence on field intensity to present, at least approximately, universal characteristics. Here we combine the nodal line technique to solve the asymptotic Schr\"odinger equation with perturbation theory. Comparing our single channel results to those obtained with the full interaction potential, we find nodal lines depending only on the field-free scattering length of the diatom to yield an approximate but universal description of the field-dressed molecule, confirming universal behavior.