Comparison of several expansions in the calculation of static electric dipole π polarizability of conjugated molecules by pertubation theory. The ground and the first excited singlet states

Matzke, P.; Chacón, Óscar; Sanhueza, Emilia M.; Trsic, Milan

doi:10.1002/qua.560060303

Cited by 20 publications

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“…In this paper the full anisotropy of the second order Table 3 Difference polarizability tensor components (• I024cm 3) for tetracene and pentacene between the 1B2u excited and 1Ag ground state as calculated from the observed shifts and using the anisotropic Lorentz approximation Varma et aL [17] ~-~ = 56.6 Matzke et aL [18] zT~ = 54.8 Barnett et al [ 3 ] Burrows et aL [19] X-~ = 29.2 Blinov et al [20] This work A-~e= 44 +-7 e) a) Cyclohexane solutions, b) benzene solutions, c) in polystyrene film, d) thin solid t'tlm, e) p-terphenyl crystal.…”

Section: Discussionmentioning

confidence: 99%

Full anisotropy of the stark effect on the 1B2u←1Ag electronic transitions of tetracene and pentacene in a ρ-terphenyl host crystal

1976

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The results of a low temperature Stark-effect study on the vis~le short axis polarized singlet transitions of tetracene and pentacene are presented and discussed.The full anisotropy of the Stark effect could be obtained reliably only by using bipolar electric field modulation together with an optical multichannel detection system. This system is also briefly described in this paper.Using the anisotropic Lorentz approximation the difference polarizability tensor components are found to be: for tetracene AaLL = 29 +-3 A s, Ac~t/L~/= 25 • 4 A s, AaNN = 5 • 5 A s; and for pentacene ACXLL = 53 • 4 A s, Ac~z~/Lt//= 90 • 8 A s, and AaNN = -11 +-9 A s. The paper emphasizes that these numbers, due to the inherent approximations of the Lorentz approximation, should be handled with great caution.

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Section: Discussionmentioning

confidence: 99%

Full anisotropy of the stark effect on the 1B2u←1Ag electronic transitions of tetracene and pentacene in a ρ-terphenyl host crystal

1976

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“…Energy expressions derived from this form involve the so-called Epstein-Nesbet denominators [12]. Trial orbitals of this nature also arise from an alternative decoupling of the CPHF equations (3) which retains some of the diagonal part of the coupling terms.…”

Section: ( F ( 0 ) -B ! O ) ) R + ( H ( L ) -E L J L ) ) I ( O ) =mentioning

confidence: 99%

Geometric approximation for molecular polarizabiities

Howat

Trsic

Goscinski

1977

Int J of Quantum Chemistry

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AbstractsMolecular polarizabilities calculated with the geometric approximation are shown to be independent of the type of perturbation theory used. Agreement with finite field calculations, including anisotropies, is obtained for small molecules. A modified procedure for including sigma and pi contributions in a differentiated way is developed within the CNDO scheme. Applications to planar conjugated systems are displayed. I1 est demontrt que les polarisabilitts moltculaires calculees par I'approximation gtomktrique sont independantes du type de thCorie des perturbations qui a ttC utiliste. Les rtsultats, y inch les anisotropies, sont en accord avec ceux obtenus par des calculs de type champ fini pour des petites molecules. Un proctdt modifit pour inclure les contributions sigma et pi d'une facoon difftrencike a t t t dCveloppCdanslecadredu schtmaCNDO.0npresente des applications i d e s systemes conjugues plans. ' Es wird gezeigt, dass mit der geometrischen Naherung berechneten molekularen Polarisierbarkeiten von dem benutzten Storungstheorietyp unabhangig sind. Die Ergebnisse-Anisotropien eingeschlossen-stimmen fur kleine Molekiile mit solchen iiberein die mittels Berechnungen von Typ "endliches Feld" erhalten werden. Ein modifiziertes Verfahren um Sigma-und Pi-Beitrage in einer differenziierten Weise einzuschliessen, wurde im Rahrnen der cNDo-Methode entwickelt. Anwendungen auf ebene konjugierte Systeme werden vorgelegt.

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“…The considerable dispersion in these results makes it difficult to assess the adequacy of any one method, although it is not unreasonable to expect that the scF-perturbation method of Ref. [7], which has given ground-state polarizabilities for a number of molecules practically within experimental error (see Table I, column 2), should have some success when applied to the excited state.…”

Section: Introductionmentioning

confidence: 99%

“…In our previous work [7] comparison was made between two perturbation schemes for the calculation of ground and excited singlet polarizabilities of a set of conjugated hydrocarbons, the two schemes being referred to as Moller-Plesset (MP) and Epstein-Nesbet (EN) expansions (the denominations EN and MP seem to have been first proposed in Ref. [23]).…”

Section: Introductionmentioning

confidence: 99%

“…The MP expansion appeared to give results in remarkably good agreement with those of experiment, both in absolute values and in correlation (see Table I, column 2) whereas the EN method, while also linearly correlated with experiment, produced absolute values that were too high. Nevertheless, it was argued [7] that the EN expansion was preferable on theoretical grounds and it was later shown [24] that the MP expansion fails to distinguish between the singlet and the triplet of the same excited configuration unless a separate minimization of each state is performed. On this basis we have preferred to use the EN expansion for all our calculations and to compensate for the higher EN values by empirically accounting for the effect of the polarization of the u electrons on the T electrons by means of Schweig's proposal [2].…”

Section: Introductionmentioning

confidence: 99%

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Singlet and triplet excited state electric dipole polarizabilities of conjugated hydrocarbons

Trsic

Sanhueza

Espinoza

1976

Int J of Quantum Chemistry

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AbstractsFirst excited singlet and triplet electric dipole polarizabilities are reported. The n polarizability is calculated by means of a modified RayleighSchrijdinger perturbation theory and an SCF-LCAO basis. The u contribution is included by an additive scheme. The polarization of the u electrons is partially accounted for through an empirical correction. Results compare satisfactorily with a configuration interaction perturbation calculation.On a calcule des polarisabilites dipolaires klectriques dans les premiers ktats excites singulets et triplets. La polarisabilite n est calcule a l'aide d'une variante de la thkorie des perturbations de Rayleigh-Schrodinger avec des fonctions SCF-LCAO. La contribution du systime u est incorporke par un schkma additif. La polarisation des klectrons u est partiellement considerie moyennant une correction impirique. Les resultats sont en accord satisfaisant avec un calcul de perturbation avec des interactions de configurations.Elektrische Dipolpolarisierbarkeiten fur die ersten angeregten Singulett-und Triplettzustande werden berichtet. Die Polarisierbarkeit der n-Elektronen wird mittels einer modifizierten Rayleigh-Schrodinger-Theorie mit einer scF-LcAo-Basis berechnet. Der uBeitrag wird mittels eines additiven Verfahrens eigenschlossen. Die Polarisierung der u-Elektronen wird zum Teil durch eine empirische Korrektur beriicksichtigt. Die Ergebnisse stimmen in befriedigender Weise mit denen einer Konfigurationswechselwirkungsberechnung uberein.

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Comparison of several expansions in the calculation of static electric dipole π polarizability of conjugated molecules by pertubation theory. The ground and the first excited singlet states

Abstract: AbstractsGround and excited singlet state dipole electric x polarizabilities of a set of conjugated molecules are calculated. Second order perturbation theory is used in the Epstein-Nesbet

Cited by 20 publications

References 12 publications

Full anisotropy of the stark effect on the 1B2u←1Ag electronic transitions of tetracene and pentacene in a ρ-terphenyl host crystal

Full anisotropy of the stark effect on the 1B2u←1Ag electronic transitions of tetracene and pentacene in a ρ-terphenyl host crystal

Geometric approximation for molecular polarizabiities

Singlet and triplet excited state electric dipole polarizabilities of conjugated hydrocarbons

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