Abstract
The new ONIOM (our own n-layered integrated molecular orbital and molecular mechanics) approach has been proposed and shown to be successful in reproducing benchmark calculations and experimental results. ONIOM3, a three-layered version, divides a system into an active part treated at a very high level of ab initio molecular orbital theory like CCSD(T), a semiactive part that includes important electronic contributions and is treated at the HF or MP2 level, and a nonactive part that is handled using force field approaches. The three-layered scheme allows us to study a larger system more accurately than the previously proposed two-layered schemes IMOMO, which can treat a medium size system very accurately, and IMOMM, which can handle a very large system with modest accuracy. This three-layered scheme has been applied to activation barriers for the Diels−Alder reaction of acrolein + isoprene, acrolein + 2-tert-butyl-1,3-butadiene, and ethylene + 1,4-di-tert-butyl-1,3-butadiene. In general, the results for both geometry optimizations and single point energy calculations agree well with benchmark predictions and experimental results. The scheme has also been applied to the transition state for the oxidative addition of H2 to Pt(P(t-Bu)3)2. The activation energy of this 83-atom reaction is predicted to be 14.2 kcal/mol with the ONIOM3(CCSD(T):MP2:MM3) method.
Keywords
Affiliated Institutions
Related Publications
<i>Ab initio</i>up to the melting point: Anharmonicity and vacancies in aluminum
We propose a fully ab initio based integrated approach to determine the volume and temperature dependent free-energy surface of nonmagnetic crystalline solids up to the melting ...
Relativistic effects in <i>a</i> <i>b</i> <i>i</i> <i>n</i> <i>i</i> <i>t</i> <i>i</i> <i>o</i> effective core potential studies of heavy metal compounds. Application to HgCl2, AuCl, and PtH
A method is described for obtaining l-dependent relativistic effective core potentials (ECPs) from Dirac–Fock self-consistent field atomic wave functions. These potentials are d...
<i>Ab initio</i> Force Constant Approach to Phonon Dispersion Relations of Diamond and Graphite
The phonon dispersion relations of diamond and graphite are calculated using an ab initio force constant method. The force constants are calculated via a self-consistent superce...
Nucleophilic Degradation of Fenitrothion Insecticide and Performance of Nucleophiles: A Computational Study
Ab initio and density functional theory (DFT) calculations have been performed to understand the destruction chemistry of an important organophosphorus insecticide O,O-dimethyl ...
Exchange and correlation energy in density functional theory: Comparison of accurate density functional theory quantities with traditional Hartree–Fock based ones and generalized gradient approximations for the molecules Li2, N2, F2
The density functional definition of exchange and correlation differs from the traditional one. In order to calculate the density functional theory (DFT), quantities accurately,...
Publication Info
- Year
- 1996
- Type
- article
- Volume
- 100
- Issue
- 50
- Pages
- 19357-19363
- Citations
- 1932
- Access
- Closed
External Links
Social Impact
Social media, news, blog, policy document mentions
Citation Metrics
Cite This
Identifiers
- DOI
- 10.1021/jp962071j