Rotation‐Vibration Spectra of Diatomic and Simple Polyatomic Molecules with Long Absorbing Paths VII. The Spectrum of Dideuteroacetylene (C2D2) in the Photographic Infrared

摘要: Twelve absorption bands of C2D2 have been observed in the photographic infrared. Eleven these show simple P and R branches with intensity alternation, i.e., they are Σ u +—Σ g + while one band, without is a difference band type Π—Π. From positions some vibrational constants ω i 0 xik determined. In addition, from rotational fine structure, constantsB [v] D For B [0] value 0.84787 cm−1 obtained. The α values α1=+0.00578, α2=+0.00302, α3=+0.00455, α4=−0.00120, α5=−0.0026 cm−1. obtains Be =0.85075 Combining (C2D2) (C2H2) yields, for internuclear distances acetylene molecule, re (C≡C)=1.2010×10−8 (C–H)=1.0637×10−8 cm very satisfactory agreement previously obtained (C2HD) (C2H2). Evidence l‐type doubling given approximate q 4 5