High-precision laser spectroscopy of the CO A(1)Pi - X-1 Sigma(+) (2,0), (3,0), and (4,0) bands

作者：Niu M L^*; Ramirez F; Salumbides E J; Ubachs W

来源：Journal of Chemical Physics, 2015, 142(4): 044302.

DOI：10.1063/1.4906244

High-precision two-photon Doppler-free frequency measurements have been performed on the CO A(1)Pi - X-1 Sigma(+) fourth-positive system (2,0), (3,0), and (4,0) bands. Absolute frequencies of forty-three transitions, for rotational quantum numbers up to J = 5, have been determined at an accuracy of 1.6 x 10(-3) cm(-1), using advanced techniques of two-color 2 + 1' resonance-enhanced multi-photon ionization, Sagnac interferometry, frequency-chirp analysis on the laser pulses, and correction for AC-Stark shifts. The accurate transition frequencies of the CO A(1)Pi - X-1 Sigma(+) system are of relevance for comparison with astronomical data in the search for possible drifts of fundamental constants in the early universe. The present accuracies in laboratory wavelengths of Delta lambda/lambda = 2 x 10(-8) may be considered exact for the purpose of such comparisons.

• 出版日期2015-1-28