Foreign gas pressure broadening and shifts of the 2S–4S two-photon transition in lithium

Abstract

We have observed broadening and shift of the 2S-4S Doppler-free two-photon transition of atomic Li by collisions with neon and argon buffer gases in a heatpipe oven. Measured broadening and shift rates are presented and compared with theoretical predictions calculated in the impact approximation using three different interaction potentials. A superposition of polarization and modified Fermi potentials gives good agreement with the experimental data.

Pressure broadening of the Li 2s–3d transition by Ne and Ar

“…The spectrum was recorded by scanning the laser over a 2.9 GHz range centred on half the 2s-3d transition frequency; this was 15 641.33 cm −1 in the case of 6 Li and 15 641.54 cm −1 in the case of 7 Li. The fine structure of the excited state and the hyperfine splitting of the ground state are resolved, resulting in a four-line spectrum.…”

“…Molecular potentials and long-range coefficients needed to model observed broadening rates can be calculated precisely in principle, raising the possibility of close contact between theory and experiment. The first studies of lithium atomic line broadening involved the resonance 2s-2p transition [1][2][3][4]; more recently, broadening of the 2s-ns [5][6][7] and 2s-n d [5] transitions has been measured.…”

Spectroscopic investigation of the 3d 2D→nf 2F transitions in lithium

“…Hence the above arguments reveal that the most probable transitions are the nf 2 F excited from the 3d 2 D intermediate level. [27][28][29][30][31]. Secondly, the presence of dc electric field in thermionic diode ion detector due to the cathode wire biasing with  5 V can also induce Stark shift and broadening in the spectral lines [25,26].…”

Long-range dispersion coefficients for Li, Li+, and Be+ interacting with the rare gases

“…However, this level of agreement is not maintained for the neon and argon C 8 and C 10 . The CR C 8 values are much too small, in the case of neon by about 30%.…”

“…[10][11][12][13] There have been some previous theoretical investigations of the Li-rare gas dispersion interactions, 14,15 with the most comprehensive work being the recent compilations by Zhang et al 16,17 Collisions between the alkaline-earth ions and the rare gases ͑RGs͒ occur in a number of different contexts. [10][11][12][13] There have been some previous theoretical investigations of the Li-rare gas dispersion interactions, 14,15 with the most comprehensive work being the recent compilations by Zhang et al 16,17 Collisions between the alkaline-earth ions and the rare gases ͑RGs͒ occur in a number of different contexts.…”