Thermal averaging of the indirect nuclear spin-spin coupling constants of ammonia: The importance of the large amplitude inversion mode

0342272 - ÚFCH JH 2011 RIV US eng J - Journal Article
Yachmenev, A. - Yurchenko, S. N. - Paidarová, Ivana - Jensen, P. - Thiel, W. - Sauer, S. P. A.
Thermal averaging of the indirect nuclear spin-spin coupling constants of ammonia: The importance of the large amplitude inversion mode.
Journal of Chemical Physics. Roč. 132, č. 11 (2010), s. 114305. ISSN 0021-9606. E-ISSN 1089-7690
R&D Projects: GA AV ČR IAA401870702
Institutional research plan: CEZ:AV0Z40400503
Keywords : ab initio calculations * ammonia * bond lengths
Subject RIV: CF - Physical ; Theoretical Chemistry
Impact factor: 2.920, year: 2010

Analytic internal-coordinate representations are reported for two accurate ab initio spin-spin coupling surfaces of the ammonia molecule, (1)J (N-15,H) and (2)J(H,H). Calculations were carried out at the level of the second-order polarization propagator approximation involving coupled-cluster singles and doubles amplitudes (CCSD) and using a large specialized basis set, for a total of 841 different geometries corresponding to 2523 distinct points on the (1)J (N-15,H) and (2)J(H,H) surfaces. The results were fitted to power series expansions truncated after the fourth-order terms. While the one-bond nitrogen-hydrogen coupling depends more on the internuclear distance, the geminal hydrogen-hydrogen coupling exhibits a pronounced dependence on the bond angle.
Permanent Link: http://hdl.handle.net/11104/0185049