- Title
- Trends in MH2n+ ion–quadrupole complexes (M = Li, Be, Na, Mg, K, Ca; n = 1, 2) using ab initio methods
- Creator
- Page, Alister J.; Wilson, David J. D.; von Nagy-Felsobuki, Ellak I.
- Relation
- Physical Chemistry Chemical Physics Vol. 12, Issue 41, p. 13788-13797
- Publisher Link
- http://dx.doi.org/10.1039/c0cp00498g
- Publisher
- Royal Society of Chemistry
- Resource Type
- journal article
- Date
- 2010
- Description
- The ground state potential energy surfaces (PESs) of MH2n+ (M = Li, Be, Na, Mg, K, Ca; n = 1, 2) have been investigated using relativistically corrected, coupled-cluster (CC) and multi-reference configuration interaction (MRCI) methods. The PESs for MH2+ (M = Li, Na, K) and MH2n+ (M = Be, Mg, Ca; n = 1, 2) exhibit global minima corresponding to C2v symmetry equilibrium structures, with local minima for D∞h and C∞v symmetry states. Conversely, the ground state PESs of LiH22+, NaH22+ and KH22+ are repulsive. In all cases, the D∞h states resulting from the insertion of Mn+ into the H2 moiety were significantly higher in energy than the co-linear C2v states. It is generally assumed a priori that these species are the result of the interaction between the metal ion charge state and the quadrupole moment of the H2 moiety. However, analysis of the functional Δαα(R(Mn+–H2)) = αα(MH2n+) − αα(Mn+) (which is effectively the difference between traceless quadrupole moments (αα) of MH2n+ and the isolated Mn+ ion computed using MRCI) as a function of Mn+–H2 distance demonstrates that a local maximum in Δαα along the molecular C2 axis is necessary for the formation of a thermodynamically stable complex. It is concluded that the topology of Δαα provides a convenient indicator of the stability of such molecular ion–quadrupole complexes.
- Subject
- potential energy surfaces; multi-reference configuration interactions; coupled-clusters; molecular ion–quadrupole complexes
- Identifier
- http://hdl.handle.net/1959.13/931065
- Identifier
- uon:10981
- Identifier
- ISSN:1463-9076
- Language
- eng
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