Knowledge Bank

Although deuterated isotopomers of organic molecules have been detected in various interstellar sources, singly deuterated isotopomers have not yet been in the interstellar medium due to a lack spectroscopic data. To aid in the analysis of interstellar spectra, rotational transitions in the ground ($\nu 1=0$)A (symmetric) and E (asymmetric, degenerate) torsional states of deuterated and normal methyl formate were measured on a TWT based broadband spectrometer. In order to minimize the rotation-torsion coupling, the data were analyzed via a diagonalization procedure involving an extended internal-axis method (IAM) Hamiltonian for angular momentum quantum number $J\le 35$.