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The ammonia dimer equilibrium dissociation energy: convergence to the basis set limit at the correlated level

Stalring, L; Schutz, M; Lindh, Roland LU ; Karlström, Gunnar LU and Widmark, Per-Olof LU (2002) In Molecular Physics 100(21). p.3389-3399
Abstract
The low-energy region of the intermolecular potential energy hypersurface (PES) of the ammonia dimer was studied at the level of second-order Moller-Plesset perturbation theory (MP2) using a very large basis set. Individual minima were located on the PES employing the counterpoise (CP) correction to account for the basis set superposition error (BSSE). Apart from these canonical MP2 calculations local MP2 (LMP2) calculations were performed. For the latter the BSSE at the correlated level is inherently absent by virtue of the local truncation of the virtual space. Results from canonical and local MP2 calculations are compared and the reliability of the LMP2 method for intermolecular complexes and clusters is discussed. The canonical MP2... (More)
The low-energy region of the intermolecular potential energy hypersurface (PES) of the ammonia dimer was studied at the level of second-order Moller-Plesset perturbation theory (MP2) using a very large basis set. Individual minima were located on the PES employing the counterpoise (CP) correction to account for the basis set superposition error (BSSE). Apart from these canonical MP2 calculations local MP2 (LMP2) calculations were performed. For the latter the BSSE at the correlated level is inherently absent by virtue of the local truncation of the virtual space. Results from canonical and local MP2 calculations are compared and the reliability of the LMP2 method for intermolecular complexes and clusters is discussed. The canonical MP2 calculations predicted five minimum structures, the four most stable ones lying energetically very close. For these four structures single point MP2 energy calculations with a further extended basis set (1024 functions for the ammonia dimer) were performed. The equilibrium dissociation energies so obtained are close to the one-particle basis set limit, as illustrated by a remaining BSSE of less than 0.2 kJ mol(-1). The geometry optimizations at the LMP2 level, using the three most stable canonical MP2 structures as initial geometries, all collapsed to a single minimum corresponding to an asymmetric structural arrangement. A canonical MP2 single point calculation, at that geometry, revealed that the LMP2 minimum structure is virtually as stable as the lowest minima on the canonical MP2 PES. Based on these calculations the global minimum of the ammonia dimer was assigned to a part of the PES represented by an asymmetric structure with an equilibrium dissociation energy of 13.5 +/- 0.3 kJ mol(-1.) (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Molecular Physics
volume
100
issue
21
pages
3389 - 3399
publisher
Taylor & Francis
external identifiers
  • wos:000178700700008
  • scopus:2342511593
ISSN
1362-3028
DOI
10.1080/00268970210162718
language
English
LU publication?
yes
id
d713745c-316d-43cc-a161-18272401166c (old id 324912)
date added to LUP
2007-11-14 14:00:44
date last changed
2017-01-01 04:22:42
@article{d713745c-316d-43cc-a161-18272401166c,
  abstract     = {The low-energy region of the intermolecular potential energy hypersurface (PES) of the ammonia dimer was studied at the level of second-order Moller-Plesset perturbation theory (MP2) using a very large basis set. Individual minima were located on the PES employing the counterpoise (CP) correction to account for the basis set superposition error (BSSE). Apart from these canonical MP2 calculations local MP2 (LMP2) calculations were performed. For the latter the BSSE at the correlated level is inherently absent by virtue of the local truncation of the virtual space. Results from canonical and local MP2 calculations are compared and the reliability of the LMP2 method for intermolecular complexes and clusters is discussed. The canonical MP2 calculations predicted five minimum structures, the four most stable ones lying energetically very close. For these four structures single point MP2 energy calculations with a further extended basis set (1024 functions for the ammonia dimer) were performed. The equilibrium dissociation energies so obtained are close to the one-particle basis set limit, as illustrated by a remaining BSSE of less than 0.2 kJ mol(-1). The geometry optimizations at the LMP2 level, using the three most stable canonical MP2 structures as initial geometries, all collapsed to a single minimum corresponding to an asymmetric structural arrangement. A canonical MP2 single point calculation, at that geometry, revealed that the LMP2 minimum structure is virtually as stable as the lowest minima on the canonical MP2 PES. Based on these calculations the global minimum of the ammonia dimer was assigned to a part of the PES represented by an asymmetric structure with an equilibrium dissociation energy of 13.5 +/- 0.3 kJ mol(-1.)},
  author       = {Stalring, L and Schutz, M and Lindh, Roland and Karlström, Gunnar and Widmark, Per-Olof},
  issn         = {1362-3028},
  language     = {eng},
  number       = {21},
  pages        = {3389--3399},
  publisher    = {Taylor & Francis},
  series       = {Molecular Physics},
  title        = {The ammonia dimer equilibrium dissociation energy: convergence to the basis set limit at the correlated level},
  url          = {http://dx.doi.org/10.1080/00268970210162718},
  volume       = {100},
  year         = {2002},
}