15min:

G. J. VÁZQUEZ AND J. M. AMERO, Centro de Ciencias Físicas, Universidad Nacional Autónoma de México (UNAM), 62251 Cuernavaca, México \quad (vaztor@fis.unam.mx).

Ab--initio SCF MRSD--CI electronic structure calculations were carried out on the NH⁺ cation. A basis set of DZ+POL quality augmented with Rydberg and bond functions was employed together with an extensive treatment of electron correlation. More than fifty electronic states of NH⁺ are reported, including doublets, quartets and sextets\footnoteJ.~M.~Amero, G.~J.~Vázquez, Int.~J.~Quantum~Chem. , 101, 396 (2005).. Leading configurations, vertical ionization energies of NH, vertical excitation energies of NH⁺ and potential energy curves are reported. Spectroscopic properties calculated for the five known bound electronic states of NH⁺ (X² , a^{4 -}, A^{2 -}, B² , C^{2 +}) are found in good agreement with experiment.

We find four new bound electronic states of NH⁺, namely, three doublets (² , ^{2 +}, ^{2 +}) and one sextet (⁶ ). A fifth bound electronic state, a quartet (⁴ ) which was reported schematically in an early SCF study is calculated for the first time over a wide range of N--H distances. Adiabatic excitation and ionization energies and spectroscopic constants are also reported for these five states\footnoteJ.~M.~Amero, G.~J.~Vázquez, Int.~J.~Quantum~Chem. , 99, 353 (2004)., as well as vertical de--excitation energies for emission from the novel states to lower lying bound states. The potential energy curve of NH²⁺(X^{1 +}) was also calculated to aid in the discussion of a Rydberg bound state of NH⁺. It is hoped that the information reported in the present work will be helpful in guiding the laboratory and/or astrophysical search for these species.