The microwave spectrum of 1-phosphapropyne, CH 3CP : Molecular structure, dipole moment, and vibration-rotation analysis

Abstract

The J = 4 ← 3 and J = 3 ← 2 rotational transitions of 1-phosphapropyne, CH 3CP, between 26.5 and 40 GHz have been studied by microwave spectroscopy. The spectrum shows the characteristic vibration-rotation satellite patterns associated with a C 3 v symmetric rotor. Apart from the most abundant isotope variant, the species 12CD 3 12C 31P, 12CD 2H 12C 31P, 12CH 2D 12C 31P, 13CH 3 12C 31P, 12CH 3 13C 31P, 13CD 3 12C 31P, and 12CD 3 13C 31P have also been studied. For 12CH 3 12C 31P the rotational constants B 0 = 4991.339 ± 0.003 MHz, D J = 0.823 ± 0.092 kHz, D JK = 66.59 ± 0.18 kHz have been determined. From these data the following structural parameters have been derived: r s( CH) = 1.107 ± 0.001 A ̊ , ∠ s (HCC) = 110.30 ± 0.09°, r s( CC) = 1.465 ± 0.003 A ̊ , r 0( CP) = 1.544 ± 0.004 A ̊ . The dipole moment has been determined as 1.499 ± 0.001 D by analysis of the Stark effect of the J = 3 ← 2, | K| = 1 line. The vibrational satellites ( v s = 1, 2, and 3) have been studied and various vibration-rotation parameters derived.