Hyperfine structure in the infrared spectrum of He3 He+4

In our recent experiment, the hyperfine splittings of He3 He+4 were observed in the infrared spectrum. Now we present an ab initio quantum-mechanical calculation of hyperfine structure in the (1-0) vibrational band of the He3 He+4 ground electronic state. The hyperfine interaction coefficients b, c, and γ are calculated by using the numerical multiconfiguration self-consistent-field method at a set of closely spaced internuclear distances and then averaged over nuclear coordinates for individual vibration-rotation states. The theoretical spectra agree well with the experimental observations.