PARALLEL CH STRETCHING BAND OF CYCLOPROPANE AT 3100-CM-1

The ν6 band of cyclopropane has been studied with appreciably higher spectral resolution than that used in previous investigations. Accurate values of the lower-state rotational constants B and DJ can be determined from a Δ2F″ analysis. The vibrational frequency and upper-state B value can be determined from the low-J transitions to unperturbed upper levels. The high-resolution studies reveal that all upper-state rotational levels having J ≧ 11 are perturbed. The following values for molecular constants were obtained: (in cm-1) B0 = 0.67024, D0J = 8.2 × 10-7, | D0JK | < 15 × 10-7, ν6 = 3101.54, B(ν6) - B0 = -0.0024. © 1969.