title: Ab initio potential energy curves for the ground and low lying excited states of NH(-) and the effect of (2)Σ(±) states on Λ-doubling of the ground state X(2)Π.
abstract: Complete basis set extrapolated ab initio potential energy curves obtained from multireference configuration interaction (MRCI) level calculations for the ground state (X(2)Π) and the a(4)Σ(-) state of NH(-) and the ground state (X(3)Σ(-)) of NH are reported. The potential energy curves for the A'(2)Σ(-) and A(2)Σ(+) states of NH(-) have been computed using the V6Z basis set at the MRCI level. Λ-doubling parameters p and q are calculated for the ground and the first excited vibrational states of the ground electronic state of NH(-) using second-orderperturbation theory. The effect of the (2)Σ(+) and (2)Σ(-) states on the Λ-doubling values is discussed. Earlier experiments had not considered the influence of the (2)Σ(-) state on p and q while fitting the spectral data. Using the computed potential energy curves and the ro-vibrational spectra including the fine splitting, we have computed the threshold for electron detachment. The result is in agreement with the experimental values of Neumark et al. [J. Chem. Phys. 1985, 83, 4364] and Farley et al. [Phys. Rev. A 1987, 35, 1099].
authors.affiliation: Department of Chemistry, Indian Institute of Technology , Kanpur, Kanpur 208016, India.
authors.forename: Saurabh
authors.initials: S
authors.lastname: Srivastava
authors.forename: N
authors.initials: N
authors.lastname: Sathyamurthy