On the Near Infrared Absorption Spectrum of Mono-Deutero-Acetylene

Abstract

The absorption spectrum of mono-deutero-acetylene has been photographed over the region 6000-10,500A in the first order of a 21-foot grating using absorbing columns up to 20 feet in length at atmospheric pressure. One band was found with origin at 10,302A. It is attributed to the molecule ${\mathrm{C}}_{2}$HD. From the rotational constants of the band and similar data from the ${\mathrm{C}}_{2}$${\mathrm{H}}_{2}$ bands, the interatomic distances in acetylene are computed as ${r}_{\mathrm{CC}}=(1.247\ifmmode\pm\else\textpm\fi{}0.008)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}8}$ cm and ${r}_{\mathrm{CH}}={r}_{\mathrm{CD}}=(0.940\ifmmode\pm\else\textpm\fi{}0.036)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}8}$ cm.