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Rotational Spectra of the Diastereomers of Soman



R D. Suenram, R S. DaBell, Angela R. Hight Walker, D J. Lavrich, David F. Plusquellic, M W. Ellzy, J M. Lochner, L Cash, J O. Jensen, A C. Samuels


The pure rotational spectrum of the nerve agent Soman has been recorded and assigned using a pulsed molecular beam Fourier transform microwave spectrometer. The spectrum consists of transitions from two different isomers that are likely the [SS] (or [RR]) and the [RS] (or [SR]) diastereomers that result from the two chiral centers in the molecule. The rotational constants for the A- states of the [SS,RR] and [RS, SR] isomers are A = 1645.3975(6) MHz, B = 591.9774(1) MHz, and C = 547.5816(1) MHz; and A = 1635.0570(4) MHz, B = 600.1488(1) MHz, and C = 556.4583(1) MHz, respectively (Type A or 1ς standard uncertainties). The conformer assignments were determined by comparison of the calculated electric dipole moments at the MP2/6-311G level of theory with the observed selection rules. Many of the rotational transitions are split into doublets. These correspond to the A- and E- torsional states arising from internal rotation of the methyl top attached directly to the phosphorous. These splittings have been used to obtain the internal rotation barrier for both isomers. This work is part of an ongoing project aimed at generating a spectral database of chemical agents and related familites of compounds.
Journal of Molecular Spectroscopy
No. 2


chemical agent, Fourier transform, GD, molecular beam, nerve agent, rotational spectrum, Soman


Suenram, R. , DaBell, R. , Hight, A. , Lavrich, D. , Plusquellic, D. , Ellzy, M. , Lochner, J. , Cash, L. , Jensen, J. and Samuels, A. (2004), Rotational Spectra of the Diastereomers of Soman, Journal of Molecular Spectroscopy (Accessed May 22, 2024)


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Created April 1, 2004, Updated February 17, 2017