The ammonia dimer equilibrium dissociation energy: convergence to the basis set limit at the correlated level
(2002) In Molecular Physics 100(21). p.33893399 Abstract
 The lowenergy region of the intermolecular potential energy hypersurface (PES) of the ammonia dimer was studied at the level of secondorder MollerPlesset 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 lowenergy region of the intermolecular potential energy hypersurface (PES) of the ammonia dimer was studied at the level of secondorder MollerPlesset 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 oneparticle 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)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/record/324912
 author
 Stalring, L; Schutz, M; Lindh, Roland ^{LU} ; Karlström, Gunnar ^{LU} and Widmark, PerOlof ^{LU}
 organization
 publishing date
 2002
 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
 13623028
 DOI
 10.1080/00268970210162718
 language
 English
 LU publication?
 yes
 id
 d713745c316d43cca16118272401166c (old id 324912)
 date added to LUP
 20071114 14:00:44
 date last changed
 20170101 04:22:42
@article{d713745c316d43cca16118272401166c, abstract = {The lowenergy region of the intermolecular potential energy hypersurface (PES) of the ammonia dimer was studied at the level of secondorder MollerPlesset 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 oneparticle 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, PerOlof}, issn = {13623028}, language = {eng}, number = {21}, pages = {33893399}, 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}, }