title: Simple systematization of vibrational excitation cross-section calculations for resonant electron-molecule scattering in the boomerang and impulse models.
abstract: Vibrational excitation (nu(f)<--nu(i)) cross-sections sigma(nu(f)<--nu(i) )(E) in resonant e-N(2) and e-H(2) scattering are calculated from transition matrix elements T(nu(f),nu(i) )(E) obtained using Fourier transform of the cross correlation function <phi(nu(f) )(R)|psi(nu(i))(R,t)>, where psi(nu(i))(R,t) approximately =e(-iH(A(2))-(R)t/h phi(nu(i))(R) with time evolution under the influence of the resonance anionic Hamiltonian H(A(2) (-))(A(2) (-)=N(2)(-)/H(2) (-)) implemented using Lanczos and fast Fourier transforms. The target (A(2)) vibrational eigenfunctions phi(nu(i))(R) and phi(nu(f))(R) are calculated using Fourier grid Hamiltonian method applied to potential energy (PE) curves of the neutral target. Application of this simple systematization to calculate vibrational structure in e-N(2) and e-H(2) scattering cross-sections provides mechanistic insights into features underlying presence/absence of structure in e-N(2) and e-H(2) scattering cross-sections. The results obtained with approximate PE curves are in reasonable agreement with experimental/calculated cross-section profiles, and cross correlation functions provide a simple demarcation between the boomerang and impulse models.
authors.affiliation: Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400 076, India.
authors.forename: Manabendra
authors.initials: M
authors.lastname: Sarma
authors.forename: S
authors.initials: S
authors.lastname: Adhikari
authors.forename: Manoj K
authors.initials: MK
authors.lastname: Mishra