High precision dipole moments in à 1A2 formaldehyde determined via Stark quantum beat spectroscopy

P. H. Vaccaro, A. Zabludoff, M. E. Carrera-Patiño, J. L. Kinsey, R. W. Field

Research output: Contribution to journalArticlepeer-review

23 Scopus citations


The high resolution technique of Stark quantum beat spectroscopy is used to examine the electric dipole moment function for the first excited singlet state (à 1A2) of formaldehyde-h2 and formaldehyde-d2. The high precision of these measurements (i.e., better than 5 parts in 104) enables detailed determination of a-axis dipole moment components (μa) for individual J = 2 rovibronic levels in the ν4 out-of-plane bending mode. In the case of 2 1,1 rotational levels, we find μa (40) = 1.4784(7) D and μa (41) = 1.4678(4) D for H 2CO. For D2CO the measured 21,1 dipole moments are μa (40) = 1.4698(6) D,μa(4 1) = 1.4693(3) D, and μae(43) = 1.4786(7) D. The state-specific variations in μa revealed by this study reflect the structural influences exerted by the pervasive S1∼ S0 nonadiabatic interactions and the pyramidally distorted equilibrium configuration which characterize the à state of formaldehyde. The origin and experimental manifestation of the out-of-plane dipole moment component (μc) in nonrigid à 1A2 formaldehyde is also discussed.

Original languageEnglish (US)
Pages (from-to)4150-4167
Number of pages18
JournalThe Journal of Chemical Physics
Issue number8
StatePublished - Jan 1 1989
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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