A Coupled Cluster Study of van der Waals Interactions of the He Atom with CN, NO and O2 Radicals

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Title:A Coupled Cluster Study of van der Waals Interactions of the He Atom with CN, NO and O2 Radicals
Creators:
Raab, Juraj
Antušek, Andrej
Biskupič, Stanislav
Urban, Miroslav
Journal or Publication Title:
Collection of Czechoslovak Chemical Communications, 69, 1, pp. 189-212
Uncontrolled Keywords:<i>Ab initio</i> calculations, HeO<sub>2</sub>, Interaction energy, HeCN, Van der Waals complexes, Potential energy surface, HeNO, Coupled cluster calculations, CCSD(T)

Abstract

The partially spin-adapted coupled cluster method with the restricted open-shell Hartree- Fock reference was applied to calculations of interaction energies between the helium atom and the three radicals, CN (<sup>2</sup>Σ), NO (<sup>2</sup>Π), and O<sub>2</sub> (<sup>3</sup>S<sub>g</sub><sup>-</sup>). Basis set dependences with medium-augmented correlation consistent basis sets were alleviated by using extrapolations to the basis set limit which were based on aug-cc-pVTZ and aug-cc-pVQZ results. The two-dimensional potential energy surfaces were fitted by exponential and polynomial functions. Minima and transition states were located. Potential energy surfaces are very floppy, especially for HeCN. This complex exhibits the weakest van der Waals interaction, the electronic interaction energy being 92 μE<sub>h</sub>. Interaction energy in HeNO is 122 μE<sub>h</sub>, almost the same as was found for HeO<sub>2</sub> (124 μE<sub>h</sub>). Considering zero-point-vibrational corrections, the dissociation energy of HeCN, HeNO, and HeO<sub>2</sub> is 4.6, 6.6, and 7.3 cm<sup>-1</sup>, respectively. This sequence of the magnitude of interaction energies and the structural data for global and local minima and transition states were compared with available literature data. No simple link between the magnitude of intermolecular forces and dipole moments and dipole polarizabilities of CN, NO, and O<sub>2</sub> was found. The low-order long-range model based on the induction and dispersion forces is completely useless in the assessment of the sequence of the size of intermolecular interactions of the HeCN, HeNO, and HeO<sub>2</sub> complexes. <p>

Title:A Coupled Cluster Study of van der Waals Interactions of the He Atom with CN, NO and O2 Radicals
Creators:
Raab, Juraj
Antušek, Andrej
Biskupič, Stanislav
Urban, Miroslav
Uncontrolled Keywords:<i>Ab initio</i> calculations, HeO<sub>2</sub>, Interaction energy, HeCN, Van der Waals complexes, Potential energy surface, HeNO, Coupled cluster calculations, CCSD(T)
Divisions:Life and Chemical Sciences > Institute of Organic Chemistry and Biochemistry > Collection of Czechoslovak Chemical Communications
Journal or Publication Title:Collection of Czechoslovak Chemical Communications
Volume:69
Number:1
Page Range:pp. 189-212
ISSN:0010-0765
E-ISSN:1212-6950
Publisher:Institute of Organic Chemistry and Biochemistry
Related URLs:
URLURL Type
http://dx.doi.org/10.1135/cccc20040189UNSPECIFIED
ID Code:2203
Item Type:Article
Deposited On:06 Feb 2009 17:16
Last Modified:06 Feb 2009 16:16

Citation

Raab, Juraj; Antušek, Andrej; Biskupič, Stanislav; Urban, Miroslav (2004) A Coupled Cluster Study of van der Waals Interactions of the He Atom with CN, NO and O2 Radicals. Collection of Czechoslovak Chemical Communications, 69 (1). pp. 189-212. ISSN 0010-0765

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