The vibration–rotation emission spectrum of CH( X 2Π)

The vibration–rotation emission spectrum of the X 2Π state of CH was observed with the McMath Fourier transform spectrometer at Kitt Peak. The 1–0, 2–1, and 3–2 bands were detected in a microwave discharge of allene in Ar and methane in He. A simultaneous fit of all of the line positions provided spectroscopic constants for v=0, 1, 2, and 3. Equilibrium molecular constants (in cm−1) include ωe=2860.4118(98), ωexe=64.1082(46), ωeye=0.2406(10), Be=14.458 62(48), αe=0.534 16(58), γe=0.001 98(15), re=1.119 83(2) Å. An RKR potential curve was calculated from the equilibrium constants.