Ab Initio Study of the CO-N₂ Complex: A New Highly Accurate Intermolecular Potential Energy Surface and Rovibrational Spectrum


A new, highly accurate ab initio ground-state intermolecular potential-energy surface (IPES) for the CO-N2 complex is presented. Thousands of interaction energies calculated with the CCSD(T) method and Dunning's aug-cc-pVQZ basis set extended with midbond functions were fitted to an analytical function. The global minimum of the potential is characterized by an almost T-shaped structure and has an energy of -118.2 cm-1. The symmetry-adapted Lanczos algorithm was used to compute rovibrational energies (up to J = 20) on the new IPES. The RMSE with respect to experiment was found to be on the order of 0.038 cm-1 which confirms the very high accuracy of the potential. This level of agreement is among the best reported in the literature for weakly bound systems and considerably improves on those of previously published potentials.



Research Center/Lab(s)

Center for High Performance Computing Research


Research financed by the National Science Centre in Poland within the OPUS 8 project No. 2014/15/B/ST4/04551. The research is a part of the program of the National Laboratory FAMO in Torun, Poland. This work was supported by the Spanish Ministerio de Ciencia e Innovacion (CTQ2011-29311-C02-01 project) and the Xunta de Galicia ("Axuda para Consolidacion e Estruturacion de unidades de investigacion competitivas do Sistema Universitario de Galicia, ED431C 2017/17"). The authors acknowledge the computational grant G51-15 from the Interdisciplinary Centre of Mathematical and Computer Modelling (ICM) of the University of Warsaw.

Keywords and Phrases

Potential Energy Surfaces; Excitation; Rotational Levels

International Standard Serial Number (ISSN)

1463-9076; 1463-9084

Document Type

Article - Journal

Document Version


File Type





© 2018 Royal Society of Chemistry, All rights reserved.

Publication Date

01 Apr 2018