# Narrowing of the Absorption Line of Light Alkali Metal Atoms in an Atmosphere of Heavy Inert Gases at Growing Radiation Intensity

A. I. Parkhomenko, A. M. Shalagin

Research output: Contribution to journalArticlepeer-review

## Abstract

The effect of narrowing of the absorption line of light alkali metal 7Li and 23Na atoms present in an atmosphere of heavy inert gas (xenon) with an increase in the external radiation intensity has been investigated. For 7Li atoms at temperature T = 300 K and buffer gas (Xe) pressure PXe=0.002 Torr, the linewidth at half maximum decreases by a factor of 1.20 with an increase in the radiation intensity from 1 µW/cm2 to 2.5 mW/cm2. For 23Na atoms at T = 600 K and $${{p}_{{{\text{Xe}}}}} = 0.01$$ Torr, the linewidth at half maximum decreases by a factor of 1.29 with an increase in the radiation intensity from 1 µW/cm2 to 6 mW/cm2. The effect of field narrowing of the absorption line is due to the following factors. First, the collisional relaxation of the velocities of light resonance particles in an atmosphere of heavy buffer particles is divided into two stages with significantly different durations: relaxation in the velocity direction (fast stage) and relaxation in the velocity magnitude (slow stage). Second, there are no collisional transitions between hyperfine components of the ground state.

Original language English 783-791 9 Optics and Spectroscopy 127 5 https://doi.org/10.1134/S0030400X19110213 Published - 1 Nov 2019

## Keywords

• absorption line
• buffer gas
• collision
• lithium
• sodium

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