High-precision laser spectroscopy of the CO A{sup 1}Π - X{sup 1}Σ{sup +} (2,0), (3,0), and (4,0) bands

Journal Article · Wed Jan 28 04:00:00 EST 2015 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.4906244· OSTI ID:22416046

Niu, M. L.; Ubachs, W. ^[1]; Ramirez, F.; Salumbides, E. J. ^[1]

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1. Department of Physics and Astronomy, and LaserLaB, VU University, De Boelelaan 1081, 1081 HV Amsterdam (Netherlands)

High-precision two-photon Doppler-free frequency measurements have been performed on the CO A{sup 1}Π - X{sup 1}Σ{sup +} 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 × 10{sup −3} cm{sup −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{sup 1}Π - X{sup 1}Σ{sup +} 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 Δλ/λ = 2 × 10{sup −8} may be considered exact for the purpose of such comparisons.

• OSTI ID: 22416046
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 4 Vol. 142; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
74 ATOMIC AND MOLECULAR PHYSICS
CARBON MONOXIDE
COLOR
COMPARATIVE EVALUATIONS
CORRECTIONS
FREQUENCY MEASUREMENT
FUNDAMENTAL CONSTANTS
INTERFEROMETRY
IONIZATION
LASER SPECTROSCOPY
MULTI-PHOTON PROCESSES
PHOTONS
QUANTUM NUMBERS
RESONANCE
WAVELENGTHS