Abstract
Calculation of accurate water-water interaction energies is of fundamental importance in computational modeling of many biological and chemical phenomena. We have obtained benchmark barrier heights for proton-exchange reactions and complexation energies in water clusters (H 2O) n (n = 1-6) by means of the high-level W1-F12 procedure. We find that lower-cost composite procedures (e.g., G4(MP2) and G4(MP2)-6X), as well as MP2 and SCS-MP2, exhibit surprisingly poor performance for the barrier heights of reactions involving multiple proton exchanges. Moreover, the performance significantly deteriorates with increasing size of the clusters. Similar observations apply to complexation energies in water clusters, and to barrier heights for proton exchange in ammonia and hydrogen fluoride clusters. We propose a modified version of G4(MP2)-6X (denoted G4(MP2)-6X+) that includes sp- and d-diffuse functions in the CCSD(T) term, which gives excellent proton-exchange barrier heights at a computational cost only slightly greater than that of standard G4(MP2). G4(MP2)-6X+ also leads to a substantial improvement over G4(MP2) and G4(MP2)-6X for the calculation of electron affinities.
| Original language | English |
|---|---|
| Pages (from-to) | 3128-3136 |
| Number of pages | 9 |
| Journal | Journal of Chemical Theory and Computation |
| Volume | 8 |
| Issue number | 9 |
| DOIs | |
| Publication status | Published - Sep 11 2012 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Computer Science Applications
Cite this
Determination of barrier heights for proton exchange in small water, ammonia, and hydrogen fluoride clusters with G4(MP2)-type, MPn, and SCS-MPn procedures-a caveat. / Karton, Amir; O'Reilly, Robert J.; Chan, Bun; Radom, Leo.
In: Journal of Chemical Theory and Computation, Vol. 8, No. 9, 11.09.2012, p. 3128-3136.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Determination of barrier heights for proton exchange in small water, ammonia, and hydrogen fluoride clusters with G4(MP2)-type, MPn, and SCS-MPn procedures-a caveat
AU - Karton, Amir
AU - O'Reilly, Robert J.
AU - Chan, Bun
AU - Radom, Leo
PY - 2012/9/11
Y1 - 2012/9/11
N2 - Calculation of accurate water-water interaction energies is of fundamental importance in computational modeling of many biological and chemical phenomena. We have obtained benchmark barrier heights for proton-exchange reactions and complexation energies in water clusters (H 2O) n (n = 1-6) by means of the high-level W1-F12 procedure. We find that lower-cost composite procedures (e.g., G4(MP2) and G4(MP2)-6X), as well as MP2 and SCS-MP2, exhibit surprisingly poor performance for the barrier heights of reactions involving multiple proton exchanges. Moreover, the performance significantly deteriorates with increasing size of the clusters. Similar observations apply to complexation energies in water clusters, and to barrier heights for proton exchange in ammonia and hydrogen fluoride clusters. We propose a modified version of G4(MP2)-6X (denoted G4(MP2)-6X+) that includes sp- and d-diffuse functions in the CCSD(T) term, which gives excellent proton-exchange barrier heights at a computational cost only slightly greater than that of standard G4(MP2). G4(MP2)-6X+ also leads to a substantial improvement over G4(MP2) and G4(MP2)-6X for the calculation of electron affinities.
AB - Calculation of accurate water-water interaction energies is of fundamental importance in computational modeling of many biological and chemical phenomena. We have obtained benchmark barrier heights for proton-exchange reactions and complexation energies in water clusters (H 2O) n (n = 1-6) by means of the high-level W1-F12 procedure. We find that lower-cost composite procedures (e.g., G4(MP2) and G4(MP2)-6X), as well as MP2 and SCS-MP2, exhibit surprisingly poor performance for the barrier heights of reactions involving multiple proton exchanges. Moreover, the performance significantly deteriorates with increasing size of the clusters. Similar observations apply to complexation energies in water clusters, and to barrier heights for proton exchange in ammonia and hydrogen fluoride clusters. We propose a modified version of G4(MP2)-6X (denoted G4(MP2)-6X+) that includes sp- and d-diffuse functions in the CCSD(T) term, which gives excellent proton-exchange barrier heights at a computational cost only slightly greater than that of standard G4(MP2). G4(MP2)-6X+ also leads to a substantial improvement over G4(MP2) and G4(MP2)-6X for the calculation of electron affinities.
UR - http://www.scopus.com/inward/record.url?scp=84866149780&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84866149780&partnerID=8YFLogxK
U2 - 10.1021/ct3004723
DO - 10.1021/ct3004723
M3 - Article
AN - SCOPUS:84866149780
VL - 8
SP - 3128
EP - 3136
JO - Journal of Chemical Theory and Computation
JF - Journal of Chemical Theory and Computation
SN - 1549-9618
IS - 9
ER -