Collect. Czech. Chem. Commun. 1993, 58, 24-28

Ab initio Calculations of the Rotation-Vibration Spectrum of Na3+

Ladislav Češpivaa, Vlasta Bonačič-Kouteckýa, Jaroslav Kouteckýa, Per Jensenb, Vojtěch Hroudac, Petr Čárskyc, Vladimír Špirkoc and Pavel Hobzac

a Institut für Physikalische und Theoretische Chemie, Freie Universität Berlin, Takustrasse 3, D-1000 Berlin 33, Germany
b Physikalisch-Chemisches Institut, Justus Liebig Universität Giessen, Heinrich-Buff-Ring 58, D-6300 Giessen, Germany
c J. Heyrovský Institute of Physical Chemistry and Electrochemistry, Czechoslovak Academy of Sciences, 182 23 Prague 8, Czech Republic


SCF, 6C-SCF, MP4 and valence-electron full CI calculations were performed in order to determine the potential surface of Na3+. A power series in the variables yi = 1 - exp (-ari), where ∆ri are bond length displacements from equilibrium, has been fitted through the surface obtained and used in a variational rotation-vibration calculations with a basis set of products of Morse-oscillator eigenfunctions and symmetric top rotational wave functions. In contrast to H3+, Na3+ behaves as a very rigid molecule and does not exhibit any anomalous anharmonicity. With our best potential surface, MP4, the predicted E' and A1' fundamental frequencies are 105.1 and 146.7 cm-1, and the harmonic E' and A1' frequencies are 106.5 and 148.3 cm-1.