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Ab initio potential energy surface and vibration‐rotation energy levels of silicon dicarbide, SiC 2
Author(s) -
Koput Jacek
Publication year - 2016
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.24464
Subject(s) - isotopologue , anharmonicity , ab initio , vibration , potential energy , electronic correlation , atomic physics , potential energy surface , ab initio quantum chemistry methods , silicon , ground state , molecular physics , physics , electron , chemistry , materials science , condensed matter physics , spectral line , quantum mechanics , molecule , optoelectronics
The accurate ground‐state potential energy surface of silicon dicarbide, SiC 2 , has been determined from ab initio calculations using the coupled‐cluster approach. Results obtained with the conventional and explicitly correlated coupled‐cluster methods were compared. The core‐electron correlation, higher‐order valence‐electron correlation, and scalar relativistic effects were taken into account. The potential energy barrier to the linear SiCC configuration was predicted to be 1782 cm −1 . The vibration‐rotation energy levels of the SiC 2 , 29 SiC 2 , 30 SiC 2 , and SiC 13 C isotopologues were calculated using a variational method. The experimental vibration‐rotation energy levels of the main isotopologue were reproduced to high accuracy. In particular, the experimental energy levels of the highly anharmonic vibrational ν 3 mode of SiC 2 were reproduced to within 6.7 cm −1 , up to as high as the v 3 = 16 state.