R-matrix calculation of low-energy electron collisions with phosphoric acid

Electron collision calculations are performed on two conformers of H3PO4, a weakly dipolar form with all OH groups pointing up and a strongly dipolar form where one OH group points down. Strong evidence is found for a broad shape resonance at about 7 eV for both conformers, although the precise parameters of this resonance are sensitive to the details of the target wavefunction used. Ten-state close-coupling calculations suggest the presence of very narrow Feshbach resonances in a similar energy region. Again both conformers behave similarly. Elastic and electronically inelastic cross sections are calculated for both conformers.