Frederick R.W. McCourt

Publications (2)0 Total impact

• Article: Ab initio potential energy surface and vibrational energies of Li3−

  Feng Wang, Frederick R.W. McCourt, Ellak I. Von Nagy-Felsobuki
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  ABSTRACT: An ab initio quantum mechanical study of the potential energy surface of Li3− has been carried out. The potential energy surface, obtained via a quantum configuration interaction calculation using single and double substitutions plus perturbatively obtained triples, on a [11s,3p,1d; 6s,3p,1d] basis set predicts the ground electronic state (1Σg+) to be linear (D∞h) with a LiLi separation of 3.03 Å at the equilibrium geometry. The surface has been fitted using a multi-dimensional least-squares procedure and has been embedded in a recently developed Eckart-Watson Hamiltonian. The low-lying vibrational band origins of Li3− have been calculated using a variational approach and rectilinear displacement coordinates.
  Chemical Physics Letters.
• Article: Glory structure in the N2N2 total integral scattering cross section. A test for the intermolecular potential energy surface

  David Cappelletti, Franco Vecchiocattivi, Fernando Pirani, Frederick R.W. McCourt
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  ABSTRACT: The first measurement of the glory structure of the total integral cross section for the scattering of N2 against N2 is reported for the collision velocity range 500–3000 m s−1. A comparison is made between the measured structure and calculations carried out within the infinite-order sudden dynamical approximation using a previously proposed N2N2 interaction potential [J. Chem. Phys. 84 (1986) 1629]. Reasonable agreement is found between the measured and calculated glory structure. There are, however, small but meaningful differences between the two results, indicating that the negative area of the interaction potential should be increased slightly.
  Chemical Physics Letters.