Collect. Czech. Chem. Commun. 2005, 70, 731-739
doi:10.1135/cccc20050731

Potential Energy Curve of N2 in Its Ground Electronic State

Vladimír Špirko

Department of Molecular Modeling, Institute of Organic Chemistry and Biochemistry, Flemingovo nám. 2, 166 10 Prague 6, Czech Republic

Abstract

The potential energy curve of N2 is constructed by morphing a very accurate (r12)-MR-ACPF ab initio potential within the framework of the reduced potential curve (RPC) approach of Jenč and Plíva. The actual morphing is performed by fitting the RPC parameters to highly accurate experimental ro-vibrational data. The resulting potential energy curve is in a close harmony with these data allowing thus for reliable prediction of the so-far unknown molecular states. The (r12)-MR-ACPF reduced potential is also used as a reference for fitting less accurate SR-CCSD and RMR-CCSD theoretical data of Li and Paldus (Li X., Paldus J.: J. Chem. Phys. 2000, 113, 9966). Though not fully quantitative, the fittings reveal high coincidence of the CCSD reduced potentials with their reference (r12)-MR-ACPF counterpart evidencing thus physical adequacy of the probed CCSD methods for rationalizing experimental data by means of the RPC approach.

Keywords: N2 molecule; Coupled-cluster calculations; Reduced potential curve; Ro-vibrational states; Ab initio calculations; Nitrogen; (r12)-MR-ACPF.

References: 24 live references.