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

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.
Authors:
;  [1] ; ;  [1] ;  [2]
  1. Department of Physics and Astronomy, and LaserLaB, VU University, De Boelelaan 1081, 1081 HV Amsterdam (Netherlands)
  2. (Philippines)
Publication Date:
OSTI Identifier:
22416046
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 142; Journal Issue: 4; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CARBON MONOXIDE; COLOR; COMPARATIVE EVALUATIONS; CORRECTIONS; FREQUENCY MEASUREMENT; FUNDAMENTAL CONSTANTS; INTERFEROMETRY; IONIZATION; LASER SPECTROSCOPY; MULTI-PHOTON PROCESSES; PHOTONS; QUANTUM NUMBERS; RESONANCE; WAVELENGTHS