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Media type:
E-Article
Title:
Quantum chemical assessment of the binding energy of CuO+
Contributor:
Rezabal, Elixabete;
Gauss, Jürgen;
Matxain, Jon M.;
Berger, Robert;
Diefenbach, Martin;
Holthausen, Max C.
imprint:
AIP Publishing, 2011
Published in:The Journal of Chemical Physics
Language:
English
DOI:
10.1063/1.3537797
ISSN:
0021-9606;
1089-7690
Origination:
Footnote:
Description:
<jats:p>We present a detailed theoretical investigation on the dissociation energy of CuO+, carried out by means of coupled cluster theory, the multireference averaged coupled pair functional (MR-ACPF) approach, diffusion quantum Monte Carlo (DMC), and density functional theory (DFT). At the respective extrapolated basis set limits, most post-Hartree–Fock approaches agree within a narrow error margin on a De value of 26.0 kcal mol−1 [coupled-cluster singles and doubles level augmented by perturbative triples corrections, CCSD(T)], 25.8 kcal mol−1 (CCSDTQ via the high accuracy extrapolated ab initio thermochemistry protocol), and 25.6 kcal mol−1 (DMC), which is encouraging in view of the disaccording data published thus far. The configuration-interaction based MR-ACPF expansion, which includes single and double excitations only, gives a slightly lower value of 24.1 kcal mol−1, indicating that large basis sets and triple excitation patterns are necessary ingredients for a quantitative assessment. Our best estimate for D0 at the CCSD(T) level is 25.3 kcal mol−1, which is somewhat lower than the latest experimental value (D0 = 31.1 ± 2.8 kcal mol−1; reported by the Armentrout group) [Int. J. Mass Spectrom. 182/183, 99 (1999)]. These highly correlated methods are, however, computationally very demanding, and the results are therefore supplemented with those of more affordable DFT calculations. If used in combination with moderately-sized basis sets, the M05 and M06 hybrid functionals turn out to be promising candidates for studies on much larger systems containing a [CuO]+ core.</jats:p>