Restricted Møller—Plesset theory for open-shell molecules

Knowles, Peter J.; Andrews, Jamie Stuart; Amos, Roger D.; Handy, Nicholas C.; Pople, John A.

doi:10.1016/s0009-2614(91)85118-g

Cited by 281 publications

(179 citation statements)

References 12 publications

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“…Once the SCF calculations were done, corrections for the many-electron correlation effects for both the neutral molecule and cation have been evaluated at the MP2 level of theory [34]. We have chosen the ROHF-MBPT variant [35,36] of the open shell spin-restricted perturbation theory for the core hole calculations.…”

Section: Computational Methodologymentioning

confidence: 99%

Relativistic study of tautomerism and core electron binding energies of thio- and selenocytosine

2012

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We applied the spin-free relativistic infiniteorder two-component method to calculate the core-electron binding energies of different tautomeric structures of thioand selenocytosine. The importance of relativistic effects in the ionization of 1s electrons was studied for selenocytosine. The present method provides a reasonably simple and reliable computational tool for calculating the core electron binding energies of molecules containing heavy atoms. The method can also be used for characterization of different tautomeric structures of nucleic acid basis.

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Section: Computational Methodologymentioning

confidence: 99%

Relativistic study of tautomerism and core electron binding energies of thio- and selenocytosine

2012

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“…Computational details: All quantum chemical calculations presented here were performed at the DFT level of theory using the Becke3-Lee-Yang-Parr (B3LYP) [43][44][45][46][47][48] hybrid functional together with a valence triple ζ (TZVP) basis set [49][50][51] for all atoms, or using spin-restricted open-shell Møller-Plesset perturbation theory (RMP2) [52][53][54] with restricted Hartree-Fock (RHF) reference functions in combination with a correlation consistent augmented triple ζ (aug-cc-pVTZ) basis set. [55,56] Density fitting was used to compute the integrals in RHF and RMP2, employing the cc-pVTZ/JKFIT and aug-cc-pVTZ/MP2FIT basis sets of Weigend.…”

Section: Methodsmentioning

confidence: 99%

A combined quantum mechanical and experimental approach towards chiral diketopiperazine hydroperoxides

Argyrakis

Köppl

Werner

et al. 2010

J of Physical Organic Chem

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To cite this version:Sabine Laschat. A combined quantum mechanical and experimental approach towards chiral diketopiperazine hydroperoxides. Journal of Physical Organic Chemistry, Wiley, 2010, 24 (8) AbstractIn order to improve hydroperoxide formation from heterocyclic compounds relating to the formation rate and to allow a suitable choice of starting materials for autoxidation, theoretical studies on a set of different amino acid-derived diketopiperazines and pyrazinoquinazolines were carried out. To estimate their reactivity towards hydroperoxide formation, bond dissociation enthalpies (BDEs) of tertiary α-C-H bonds as well as reaction enthalpies to the corresponding hydroperoxides were calculated at the B3LYP/TZVP and RMP2/aug-cc-pVTZ level of theory. The EvansPolanyi relation was then used to correlate substrate reactivity with calculated BDEs.Thermal and zero point vibrational energy corrections were determined in the classical harmonic oscillator-rigid rotor-particle in a box model. While for the investigated set of diketopiperazines BDEs of 318.8-327.0 kJ mol -1 were found, BDEs for pyrazinoquinazolines spread between 248.4-368.4 kJ mol -1 at the B3LYP/TZVP level of theory. A selected subset of heterocycles was converted to the corresponding hydroperoxides and the diketopiperazines were obtained in up to 39 % yield after 5-7 days, whereas the pyrazinoquinazolines hydroperoxides were isolated in up to 67 % yield after 24 hours. Thus, replacing an amido moiety in an N-aryl-imino moiety when using pyrazinoquinazolines instead of diketopiperazines leads indeed to an improved captodative stabilization of the radical intermediate. Furthermore the theoretical calculations allowed a distinctive forecast of the preferred regioisomeric hydroperoxide.

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“…RMP theory 19,20 is perhaps the most straightforward of the open-shell theories investigated here. The zeroth-order Hamiltonian is defined to be the occupied/occupied and virtual/virtual blocks of the spin orbital Fock operator…”

Section: A Restricted Mo " Ller-plesset Theory (Rmp)mentioning

confidence: 99%

“…Additionally, Ĥ ͑0͒ is spin dependent, resulting in spin contaminated perturbed wave functions. However, it has been shown 19,25 that the perturbed energies are spin projected, eliminating direct but not indirect spin contamination. 32 …”

Section: ͑17͒mentioning

confidence: 99%

See 1 more Smart Citation

On the energy invariance of open-shell perturbation theory with respect to unitary transformations of molecular orbitals

Crawford

Schaefer

Lee

1996

The Journal of Chemical Physics

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Restricted openshell Hartree-Fockbased manybody perturbation theory: Theory and application of energy and gradient calculations J. Chem. Phys. 97, 6606 (1992) A number of recently proposed single-reference open-shell perturbation theories based on a spin-restricted open-shell Hartree-Fock reference function are examined, with an emphasis on a consistent formalism within which the theories may be compared. In particular, the effect of unitary transformations among the molecular orbitals on the energy is discussed. Of the seven different perturbation theories examined here, the restricted Mo "ller-Plesset theory, open-shell perturbation theory method 1, the method of Hubač and Č ársky, Z-averaged perturbation theory, and invariant open-shell perturbation theory methods are found to be invariant to all types of rotations for which the reference wave function is unaffected, though all are invariant to transformations of a more limited nature. Explicit equations for the generalized invariant forms of each perturbation theory are presented, in order to provide working equations for extension of the theories to local correlation schemes or coupled-cluster perturbational corrections, among others.

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Restricted Møller—Plesset theory for open-shell molecules

Cited by 281 publications

References 12 publications

Relativistic study of tautomerism and core electron binding energies of thio- and selenocytosine

Relativistic study of tautomerism and core electron binding energies of thio- and selenocytosine

A combined quantum mechanical and experimental approach towards chiral diketopiperazine hydroperoxides

On the energy invariance of open-shell perturbation theory with respect to unitary transformations of molecular orbitals

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