Burrow Paul D, Gallup Gordon A, Modelli Alberto
Department of Physics and Astronomy, University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0111, USA.
J Phys Chem A. 2008 May 1;112(17):4106-13. doi: 10.1021/jp7109143. Epub 2008 Mar 27.
The temporary anion states of trimethyl phosphate and several compounds bearing the P=O group were explored using electron transmission spectroscopy and ab initio calculations to determine if these states have the characteristics of the pi* resonances usually associated with multiple bonds. No evidence was found for this in (CH3O)3PO and, by extension, we do not expect them to appear in the phosphate group of DNA. Cl3PO, however, does display such characteristics to some extent, and we show that they arise from the spatial properties of the sigma* (P-Cl) orbitals rather than from multiple PO bonding. A novel computational means to explore effects due to the relative size of a molecular orbital and that of the angular momentum barrier responsible for confining the additional electron is presented.
