Near-infrared high resolution diode laser spectrum of the CH21B1 ← ã1A1 transition

Christopher Fockenberg, Andrew J. Marr, Trevor J. Sears, Bor Chen Chang

Research output: Contribution to journalArticlepeer-review

19 Scopus citations


A new diode laser-based spectrometer operating at wavelengths close to 1 μm has been constructed for transient absorption measurements in the gas phase. Using a dual beam detection system for noise cancellation, the minimum detectable absorption was found to be 1 × 10-4 in 0.5 μsec. The sensitivity of the instrument is illustrated by the observation of previously undetected spectra of singlet methylene (CH2) between 9780 and 10070 cm-1. Rovibronic transitions involving two Ka = 1 levels, nominally associated with v2(bent) = 1 and 2, in the upper, b̃1B1, state have been assigned. These levels are the lowest so far observed for methylene in this electronic state and their positions provide new information on the shape of the bending potential for the molecule at energies approaching that at which the two lowest singlet states (ã1A1 and b̃1B1) of the molecule become degenerate at the linear configuration.

Original languageEnglish
Pages (from-to)119-125
Number of pages7
JournalJournal of molecular spectroscopy
Issue number2
StatePublished - Feb 1998


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