Pressure effect on hyperfine CPT resonance of ground-state Li atoms in glass hot-vapor cell

We report the hyperfine splitting frequency of ground-state lithium atoms. The frequency shift is induced by the collisions to helium and xenon buffer gases. Coherent population-trapping resonance between the hyperfine levels enables the frequency measurements in the range of pressure from 2 to $54\text{kPa}$ and temperature from 260 to $400{}^{\circ }\text{C}$ in borosilicate-glass cells. The buffer-gas density is self-consistently calibrated from the hyperfine splitting in the sealed cells. The resonance frequency and the line width provide an insight into collision-induced spin dynamics, where hyperfine-shift, spin-rotation, and spin-exchange interactions play an important role in atomic lithium vapor and buffer gas.