Premium
On the accuracy of molecular properties by coupled‐cluster methods for some difficult examples: Oxygen atom, iron atom, and cyano radical
Author(s) -
Urban Miroslav,
Watts John D.,
Bartlett Rodney J.
Publication year - 1994
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560520121
Subject(s) - polarizability , coupled cluster , chemistry , dipole , ionization energy , atom (system on chip) , atomic physics , molecule , computational chemistry , ionization , physics , ion , computer science , embedded system , organic chemistry
Coupled‐cluster ( CC ) methods at the level of CCSD , CCSD + T ( CCSD ), CCSD ( T ), CCSDT ‐1, and CCSDT ‐3 are applied to calculations of the dipole moment and polarizability of the CN molecule, ionization potentials and electron affinities of the oxygen and iron atoms and CN molecule, and the energy splitting of the 5 D and 5 F states of the iron atom. Both UHF and ROHF references are applied. Extended basis sets are used in some comparison of CC data to experiment. All calculated atomic and molecular properties are known as challenging problems, suitable for a careful analysis of the performance of sophisticated versions of the CC approach. Attention is paid to energy terms distinguishing CCSD ( T ) from CCSD + T ( CCSD ). We exploit results from various iterative and noniterative high‐level CC methods in the assessment of error bars in calculations of atomic and molecular properties. © 1994 John Wiley & Sons, Inc.