TY - JOUR

T1 - Satellites of the resonance transitions of alkali atoms in mixtures with CF4

AU - Alekseev, V. A.

AU - Pastor, A. A.

AU - Pazgalev, A. S.

AU - Petrov, P. A.

AU - Serdobintsev, P. Yu

AU - Vartanyan, T. A.

N1 - Funding Information: This work was supported by the ITMO University fellowship grant (contract No. 59.06.04 - 05 / 08 - 19 ). Publisher Copyright: © 2020 Copyright: Copyright 2020 Elsevier B.V., All rights reserved.

PY - 2021/1/1

Y1 - 2021/1/1

N2 - The absorption and luminescence excitation spectra of gas phase mixtures of alkali metals atoms A (A = K, Rb, Cs) with carbon tetrafluoride molecules CF4 are studied in the region of transitions from the ground state A(2S1/2) to the lowest resonance states A(2P1/2, 3/2). It is shown that these transitions have intense satellites corresponding to the simultaneous vibrational excitation of the carbon tetrafluoride molecule, A(2S1/2) + CF4(v3=0) + hv → A(2P1/2, 3/2) + CF4(v3=1), where v3 is the IR active mode of CF4 with a vibrational quantum energy of 1281 cm–1. The satellites are relatively narrow bands (FWHM ~ 30 cm–1) slightly (< 10 cm–1) shifted to the red from the energies corresponding to the asymptotes A(2PJ) + CF4(v3=1), J=1/2, 3/2. The spectral width and position of the satellites indicate that these transitions occur at relatively large atom-molecule distances. In contrast to the majority of the studied before pair excitation processes in the gas phase, the intensity borrowing mechanism responsible for the observed satellite bands cannot be explained by the dipole-dipole interaction. Possible alternative mechanisms are discussed. It is also established that mixtures with CF4 are chemically stable including at elevated temperatures up to at least 200°C and their optical excitation results in resonance luminescence of alkali atoms. As compared to Ar, collisions with CF4 provides a higher rate of the population transfer between the A(2P1/2) and A(2P3/2) states. These results indicate that CF4 may be used as a component of the active medium of diode pumped alkali lasers.

AB - The absorption and luminescence excitation spectra of gas phase mixtures of alkali metals atoms A (A = K, Rb, Cs) with carbon tetrafluoride molecules CF4 are studied in the region of transitions from the ground state A(2S1/2) to the lowest resonance states A(2P1/2, 3/2). It is shown that these transitions have intense satellites corresponding to the simultaneous vibrational excitation of the carbon tetrafluoride molecule, A(2S1/2) + CF4(v3=0) + hv → A(2P1/2, 3/2) + CF4(v3=1), where v3 is the IR active mode of CF4 with a vibrational quantum energy of 1281 cm–1. The satellites are relatively narrow bands (FWHM ~ 30 cm–1) slightly (< 10 cm–1) shifted to the red from the energies corresponding to the asymptotes A(2PJ) + CF4(v3=1), J=1/2, 3/2. The spectral width and position of the satellites indicate that these transitions occur at relatively large atom-molecule distances. In contrast to the majority of the studied before pair excitation processes in the gas phase, the intensity borrowing mechanism responsible for the observed satellite bands cannot be explained by the dipole-dipole interaction. Possible alternative mechanisms are discussed. It is also established that mixtures with CF4 are chemically stable including at elevated temperatures up to at least 200°C and their optical excitation results in resonance luminescence of alkali atoms. As compared to Ar, collisions with CF4 provides a higher rate of the population transfer between the A(2P1/2) and A(2P3/2) states. These results indicate that CF4 may be used as a component of the active medium of diode pumped alkali lasers.

KW - PAIR ABSORPTION

KW - LASER

KW - METHANE

KW - SPECTRA

KW - CS

KW - RB

UR - http://www.scopus.com/inward/record.url?scp=85091739028&partnerID=8YFLogxK

UR - https://www.mendeley.com/catalogue/70076f2c-ecc7-313b-97a6-6f030618e43f/

U2 - 10.1016/j.jqsrt.2020.107339

DO - 10.1016/j.jqsrt.2020.107339

M3 - Article

AN - SCOPUS:85091739028

VL - 258

JO - Journal of Quantitative Spectroscopy and Radiative Transfer

JF - Journal of Quantitative Spectroscopy and Radiative Transfer

SN - 0022-4073

M1 - 107339

ER -