Dissociative electron attachment to the H2O molecule. I. Complex-valued potential-energy surfaces for the B-2(1), (2)A(1), and B-2(2) metastable states of the water anion

We present the results of calculations defining global, three-dimensional representations of the complex-valued potential-energy surfaces of the B-2(1), (2)A(1), and B-2(2) metastable states of the water anion that underlie the physical process of dissociative electron attachment to water. The real part of the resonance energies is obtained from configuration-interaction calculations performed in a restricted Hilbert space, while the imaginary part of the energies (the widths) is derived from complex Kohn scattering calculations. A diabatization is performed on the (2)A(1) and B-2(2) surfaces, due to the presence of a conical intersection between them. We discuss the implications that the shapes of the constructed potential-energy surfaces will have on the nuclear dynamics of dissociative electron attachment to H2O.