The double minimum potential in the spectrum of HCOF

Rotational analyses conducted together with theoretical calculations of the relative intensities for vibronic transitions involving an excited state with a double minimum potential have led to confirmation of the previously established vibrational analysis and to a full characterization of the double-minimum potential function. The origin band at 37 490 cm^?1 has been shown to consist of the two transitions 6₀⁰ (true origin) and 6₀¹ separated by only 0.5 cm^?1 and with rotational structures corresponding to type C, allowed, and hybrid type AB, Herzberg-Teller induced, bands respectively.