Approximate molecular orbital study of organic positron and positronium complexes

Madia, W.J.; Schug, John C.; Nichols, Alan L.; Ache, Hans J.

doi:10.1021/j100619a010

Cited by 13 publications

(8 citation statements)

References 10 publications

(11 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The values obtained from Equation 12 are only 8.2% higher than those from Equation 11. This kind of comparison provides one of the few available tests of the quality and internal consistency of a semiempirical method, and the concordance here is very encouraging.…”

mentioning

confidence: 51%

“…More recently, the complete neglect of differential overlap ( CNDO ) method (JO) was parameterized for positron/Ps-molecule-bound states (11). This is in very much the same spirit as our own work, described in this chapter.…”

Section: "Previous Workmentioning

confidence: 91%

“…It is interesting to study the molecular orbitals in e + C6H5F as a prototype. The molecule has C2v symmetry and 33 MOs with the follow ing symmetry: Ax (15), A2 (2), Bi (5), and B2 (11). The pi MOs are A2 and Bi.…”

Section: Aamentioning

confidence: 99%

See 2 more Smart Citations

Theory of the Structures of Intermediates in Positronium Chemistry

Schrader

1979

Advances in Chemistry

View full text Add to dashboard Cite

Different mechanisms for positron annihilation in a chemical medium are distinguished by different intermediates. All meas ured annihilation properties (lifetime, angular correlation, etc.) are in fact properties of that intermediate which exists just prior to annihilation. The structures of these inter mediates have been studied quantum mechanically as an adjunct to laboratory measurement of annihilation proper ties. The quantum mechanical studies involve calculating approximate wave functions for one-positron, many-electron systems. Some scattering states have been studied in this way for atoms, but all molecular studies so far focus on bound positrons or positronium atoms The questions of whether such bound states exist for particular molecules, and of the properties of those bound states which do exist, have been addressed in several studies. The most successful of these (1) permits one to examine positron/positronium -molecule interactions at a more fundamental level than was hitherto possible. P ositron/positronium (Ps) chemistry takes place somewhere between the beginning of the initial positron/Ps-reactant molecule encounter and annihilation. What happens in the intermediate region of the reaction coordinate is of great interest to the chemist. If we can understand this region at the level of positron/Ps interactions with individual molecules, we can map out the whole of positron/Ps chemistry. Our knowledge of this intermediate region is presently very hazy. The experimental literature contains many speculations about structures of intermediates. Frequently these speculations are quite sensible and are widely and uncritically accepted by the community, but are incorrect. A

show abstract

mentioning

confidence: 51%

Section: "Previous Workmentioning

confidence: 91%

See 1 more Smart Citation

Theory of the Structures of Intermediates in Positronium Chemistry

Schrader

1979

Advances in Chemistry

View full text Add to dashboard Cite

show abstract

“…15 More complicated systems, e.g., Ps halides, Psmolecule compounds, etc., have been calculated by HF, 5,18 -23 density functional theory, 24,25 and semi-empirical CNDO. 26,27 Existence of Ps halides has been confirmed ex-perimentally except for PsF, and the two-photon annihilation rates and the angular correlation have been measured. 2 The two-photon angular correlation curves calculated by numerical Hartree-Fock 18 are in excellent agreement with the experimental values for PsCl.…”

Section: Introductionmentioning

confidence: 84%

Application of pair correlation theory to positronium compounds

Saito

Sasaki

1995

The Journal of Chemical Physics

View full text Add to dashboard Cite

Extension of weak orthogonality ͑WO͒ techniques developed by Szalewicz et al. and coupled pair equations derived by Jeziorski et al. to positronium compounds are presented. These methods enable us to calculate many-electronic positronium compounds with explicitly correlated functions. These methods were applied to positronium hydride ͑PsH͒ with Hylleraas-type functions ͑HTF's͒, and the total energies, the positron-electron two-photon annihilation rates, and the positronium binding energies were calculated. Extended coupled pair equations were solved by CEPA͑2͒-type, complete coupled pair ͑CCP͒ procedures, and independent pair approximation ͑IPA͒ of CCP. For the total energies, IPA, CEPA͑2͒, and CCP procedures gave Ϫ0.78899, Ϫ0.78238, and Ϫ0.77471 au, respectively. For the two-photon annihilation rates, the respective procedure gave 2.088, 2.064, and 1.972 ns Ϫ1 , respectively.

show abstract

“…Recent years have witnessed the publication of several papers and reviews dealing with the interaction of positrons with gases, liquids, and solids [I]. The [8,91 based on the CNDO method have been carried out for several molecular species. However, owing to the lack of experimental or ab initio data to guide in the parametrization, the reliability of the CNDO methods is subject to question.…”

Section: Introductionmentioning

confidence: 99%