High-Level Ab-Initio Calculation on the NiO₂ System

Journal Article · Wed Sep 20 04:00:00 EDT 2006 · Chemical Physics Letters, 428(4-6):277-282

DOI:https://doi.org/10.1016/j.cplett.2006.07.075· OSTI ID:895454

Song, Jie; Apra, Edoardo; Khait, Yuri; Hoffmann, Mark R; Kowalski, Karol

Several high-level ab-initio methods were employed in studies of the narrow singlet-triplet separation of the cyclic dorm of the nickel dioxide (NiO?). It is shown that the complete visions of the locally renormalized couples cluster method with singles, doubles, and noniterative triples (LR-CCSD(T)) approach, in contrast to the standard CCSD(T) method, provides results in concert with predictions of the density functional theory (DFT) and internally contracted multi-reference configuration interaction method (IIC-MCRCI), which favor the triplet state to be the lowest one. Relevant discussion of several aspects related to underlying CCSD calculations, indicate that the dominate roll of singly excited amplitudes violates the paradigm about the leading role to two-body effect in description of the correlation energy. These results are compared with the results of the second order Generalized Van Vleck Perturbation Theory (GVVPPT2) approach which supports the CCSD(T) predictions.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 895454
• Report Number(s): PNNL-SA-50204; KP1303000
• Journal Information: Chemical Physics Letters, 428(4-6):277-282, Journal Name: Chemical Physics Letters, 428(4-6):277-282
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
AMPLITUDES
CONFIGURATION INTERACTION
DENSITY FUNCTIONAL METHOD
ELECTRON CORRELATION
NICKEL OXIDES
PERTURBATION THEORY
TRIPLETS