Eur. Phys. J. D 33, 323-327 (2005)
https://doi.org/10.1140/epjd/e2005-00047-3

Laser spectroscopic investigation of Ca atoms in liquid helium

Comparison between spectral properties for liquid helium-3 and helium-4

¹ Department of Physics, Toyama University, Gofuku, Toyama 930-8555, Japan
² Department of Molecular Structure, Institute for Molecular Science, Myodaiji, Okazaki 444-8585, Japan

Corresponding author: ^a moriwaki@sci.toyama-u.ac.jp

Received: 21 September 2004
Revised: 14 March 2005
Published online: 19 April 2005

Abstract

Excitation and emission spectra of the S₀ – P₁ and P – S₁ transitions of Ca atoms implanted not only in liquid ⁴He but also in liquid ³He have been measured. It has been found that the excitation spectra for liquid ³He show considerably smaller widths and peak shifts from transition wavelengths of a free Ca atom, in comparison with those for liquid ⁴He. These spectral characteristics have been well reproduced by our theoretical calculation based on a vibrating bubble model. This calculation has shown that, due to a significant difference in surface tension between the two liquids, the radius of a bubble formed around Ca in liquid ³He is larger than the one in ⁴He, and that this fact as well as the smaller number density of He atoms in liquid ³He cause weaker perturbation for Ca, resulting in the smaller peak shift and width for liquid ³He.