Rotationally resolved infrared-ultraviolet double resonance spectroscopy in molecular D2CO and HDCO

Brian J. Orr*, Gary F. Nutt

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

26 Citations (Scopus)


Rotationally resolved infrared-ultraviolet double resonance (IRUVDR), consisting of sequentially excited rovibrational and rovibronic transitions sharing a common intermediate molecular level, is demonstrated. The technique employs pulsed CO2 and tunable dye lasers and is applied to the molecules D2CO and HDCO. For D2CO, infrared pumping produces 100fold population enhancement in specific rotational sublevels of the v4 = 1 level of the X̃1A1 electronic ground state, followed by ultraviolet excitation in the 365-nm 410 band of the à 1A2 ← X̃ 1A1 electronic system. This ultraviolet excitation occurs at a specific set of dye laser frequencies, determined by the preceding rovibrational transition, and is detected by molecular fluorescence in the visible region. Similar effects observed in HDCO involve rovibrational pumping to either the v6 = 1 or v5 = 1 levels and give rise to enhanced rovibronic transitions in the 610 and 510 bands of the à ← X̃ system, respectively. The resulting IRUVDR spectra enable detailed spectroscopic assignments to be made and are consistent with previous results from infrared and ultraviolet absorption, laser Stark, and infrared-radiofrequency double resonance spectroscopy. Collision-induced satellite structure, arising from rotational relaxation of the intermediate rovibrational level in the IRUVDR sequence, is also reported.

Original languageEnglish
Pages (from-to)272-287
Number of pages16
JournalJournal of Molecular Spectroscopy
Issue number1
Publication statusPublished - Nov 1980
Externally publishedYes


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