Laser excited resonance fluorescence in formaldehyde

Abstract

The 3375 Å line of the Kr⁺ laser has been used to excite a single rovibronic transition of the ?¹A₂–?¹A₁ system of formaldehyde. Fluorescence from the upper level to the ground electronic state forms vibrational progressions in the carbonyl stretch (ν₂^″), the symmetric in plane bend (ν₃^″) and twice the out of plane bend (2ν₄^″), extending over 10 000 cm⁻¹ to the red of the exciting line. The rotational structure has been resolved and effective rotational A constants have been obtained. Vibrational constants and anharmonicities have been calculated.