Intermolecular Effects on Third Order Nonlinear Optical Properties

1992 ◽  
Vol 247 ◽  
Author(s):  
D. S. Dudis ◽  
A. T. Yeates ◽  
H. A. Kurtz

ABSTRACTHartree-Fock ab initio calculations have been used to examine the magnitude of non-polar intermolecular interactions on polarizabilities and second hyperpolarizabilities. In the present case two ethylene molecules were examined in a cofacial interaction. Basis set requirements and correlation effects were considered in deriving the intermolecular potential. Two basis sets were considered for the intermolecular interactions at the Hartree-Fock level, while one set of calculations was performed with corrections for correlation. It is found that intermolecular contacts at the van der Waals distance has little effect on the molecular second hyperpolarizability, but it is not clear what the effect would be for longer oligomers.

1999 ◽  
Vol 579 ◽  
Author(s):  
Mamoun M. Bader

ABSTRACTWe report herein the results of coupled perturbed Hartree-Fock (CPHF) ab initio extended basis set calculations on the geometric structures, dipole moments, static first-order (α), second-order (β), and third-order polarizabilities (λ) of a series of fused heterocyclic aromatic compounds based on quinoline. The effects of the presence/absence of the heteroatom as well as the introduction of other substituents at various positions in the ring system on these molecular properties are described. The effect of the presence of N-oxide is also examined. Suggestions for the design of heterocyclic systems with enhanced polarizabilities are made.


2008 ◽  
Vol 73 (11) ◽  
pp. 1391-1414 ◽  
Author(s):  
István Mayer

Some results of mathematical character concerning the theory of intermolecular interactions and the BSSE problem are presented. It is shown that the concept of complete basis set may be introduced for intermolecular potential surfaces only by considering explicitly the limiting process in which the basis sets of both monomers approach completeness simultaneously. That does not lead to any overcompleteness problem if we do not postulate the existence of two complete basis sets from the outset. The intimate connection between the BSSE and the differences of some biorthogonal integrals and their "original" counterparts is also discussed. The operator of BSSE is given in terms of such differences. It is shown that in a special case, when only the overlap of the occupied orbitals is considered, the "bi-expectation" value of the energy coincides with the conventional expectation value for the single determinant wave function built up of the unperturbed orbitals of the individual monomers. It is discussed, by using a model of the biorthogonal perturbation theory, why the conceptually fully different a priori (CHA) and a posteriori (CP) schemes of BSSE correction usually give very close numerical results. (The necessary biorthogonal perturbation formalism is developed in the Appendices.) The results give justification for the additivity assumptions inherent in the CP method.


2021 ◽  
Vol 68 (1) ◽  
pp. 170-177
Author(s):  
Fatemeh Mostaghni

In this study, 4-(4,5-Diphenyl-1H-imidazole-2-yl) phenol is successfully synthesized, and its nonlinear optical properties (NLO) are investigated both experimentally and theoretically. Theoretical investigations have been done by using TDDFT and B3LYP functional with usual 6-31+G(d,p) basis set. The results of HOMO-LUMO and NBO analysis show the low energy gap, high total dipole moment, and hyperpolarizabilities (β, γ) as well as the presence of dipolar excited states with relatively significant dipole-moment changes which are linked to the nonlinearity. The z-scan technique confirmed the NLO properties of title compound. The nonlinear absorption coefficient, refractive index, and third-order susceptibility were found to be 4.044 × 10−1 cmW−1, 2.89 × 10−6 cm2W−1 and 2.2627 × 10−6 esu, respectively. The negative sign of n2 indicated the occurrence of self-defocusing nonlinearity. The results show that the title compound can been used as potential NLO material.


2021 ◽  
Author(s):  
Guifen Lu ◽  
Peng Zhang ◽  
Yuanyuan Fang ◽  
Yongjie Gao ◽  
Qikang Hu

A series of trans-A2B cobalt corroles, represented as [Cor(p-RPh)2(p-NO2Ph)]Co(PPh3) (1-5), where Cor is trianion of corrole, R is a CN, F, CH3, C(CH3)3 or PhCH2O on the para-position of the...


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