The second-order nonlinear optical properties of thiophene S,S -dioxides derivatives were studied by using the ZINDO-SOS method. The computed results show that the thiophene S,S -dioxide derivatives exhibit larger sec...The second-order nonlinear optical properties of thiophene S,S -dioxides derivatives were studied by using the ZINDO-SOS method. The computed results show that the thiophene S,S -dioxide derivatives exhibit larger second-order polarizabilities than their thiophene precursors. In order to clarify the origin of the different NLO responses among these chromophores, their electron properties and frontier orbital properties were investigated as well. These thiophene S,S -dioxides derivatives are good candidates for their application in electro-optical device due to their high nonlinearities, good thermal and photo stabilities.展开更多
Based on HYPERCHEM, the structures of five phthalocyanie compounds were optimized with PM3 and their visible absorption maxima were calculated with ZINDO/S method by selecting appropriate p-p overlap weighting factor ...Based on HYPERCHEM, the structures of five phthalocyanie compounds were optimized with PM3 and their visible absorption maxima were calculated with ZINDO/S method by selecting appropriate p-p overlap weighting factor (OWFp-p), the agreement with experiment was excellent. The relationship between OWF- and molecular structure parameters was obtained by the method of stepwise regression and was explained in terms of quantum theory. OWF-=0.58126+0.04562ANC1+0.03839X. Where, ANC1 and X are the symbols of average net charges on coordinated bonded nitrogens and electronegativity of central atom, respectively.展开更多
Electronic emission spectra of N2, (N2)2, (N2)5 O2, (O2)2, (O2)5, H2O, (H2O)5, CO2, (CO2)2, CO2..H2O, NH3 and NH3.H2O situated in the electric field of 0.001, 0.005, 0.01 0.05 and 0.1 a.u. were simulated involving Mon...Electronic emission spectra of N2, (N2)2, (N2)5 O2, (O2)2, (O2)5, H2O, (H2O)5, CO2, (CO2)2, CO2..H2O, NH3 and NH3.H2O situated in the electric field of 0.001, 0.005, 0.01 0.05 and 0.1 a.u. were simulated involving Monte Carlo optimization followed by the ZINDO/S approach. The simulated spectra showed irregular dependence on the energy of the electric field applied. Molecules without influence of the electric field emit in the vacuum ultraviolet region. Applied electric field only in case of (O2)5 generated transitions above 200 nm. The mapping of isosurface of the investigated molecules revealed that the electric field applied redistributed the charge densities in the molecules in the manner approximately parallel to the energy of the field. Applied electrical field resulted in an increase in the water acidity and ammonia basicity.展开更多
Novel low dipole moment (μ) and large first hyperpolarizability (β) electrooptic chromophores have been designed based on the special characteristic of reversed dipole moment in the excited state of exocyclic double...Novel low dipole moment (μ) and large first hyperpolarizability (β) electrooptic chromophores have been designed based on the special characteristic of reversed dipole moment in the excited state of exocyclic double bond (ECDB) conjugated bridge by the optimization of the substituted method, and their electronic and second-order nonlinear optical properties have been theoretically investigated by employing the AM1/FF and ZINDO/S-CI approaches. By extending the conjugation length and optimizing the donor/acceptor strength, the oscillator strength of the excited transition that contributes to the molecular nonlinearity can be further enhanced. The designed chromophores possess a larger figure of merit (FOM) than that of 4-N,N-dimethylamino-4’-nitrostilbene (DANS), and lower (5 D) ground state dipole moment.Novel low dipole moment (μ) and large first hyperpolarizability (β) electrooptic chromophores have been designed based on the special characteristic of reversed dipole moment in the excited state展开更多
基金Supported by the National Natural Science Foundation of China(No. 2 98730 2 5 )
文摘The second-order nonlinear optical properties of thiophene S,S -dioxides derivatives were studied by using the ZINDO-SOS method. The computed results show that the thiophene S,S -dioxide derivatives exhibit larger second-order polarizabilities than their thiophene precursors. In order to clarify the origin of the different NLO responses among these chromophores, their electron properties and frontier orbital properties were investigated as well. These thiophene S,S -dioxides derivatives are good candidates for their application in electro-optical device due to their high nonlinearities, good thermal and photo stabilities.
文摘Based on HYPERCHEM, the structures of five phthalocyanie compounds were optimized with PM3 and their visible absorption maxima were calculated with ZINDO/S method by selecting appropriate p-p overlap weighting factor (OWFp-p), the agreement with experiment was excellent. The relationship between OWF- and molecular structure parameters was obtained by the method of stepwise regression and was explained in terms of quantum theory. OWF-=0.58126+0.04562ANC1+0.03839X. Where, ANC1 and X are the symbols of average net charges on coordinated bonded nitrogens and electronegativity of central atom, respectively.
文摘Electronic emission spectra of N2, (N2)2, (N2)5 O2, (O2)2, (O2)5, H2O, (H2O)5, CO2, (CO2)2, CO2..H2O, NH3 and NH3.H2O situated in the electric field of 0.001, 0.005, 0.01 0.05 and 0.1 a.u. were simulated involving Monte Carlo optimization followed by the ZINDO/S approach. The simulated spectra showed irregular dependence on the energy of the electric field applied. Molecules without influence of the electric field emit in the vacuum ultraviolet region. Applied electric field only in case of (O2)5 generated transitions above 200 nm. The mapping of isosurface of the investigated molecules revealed that the electric field applied redistributed the charge densities in the molecules in the manner approximately parallel to the energy of the field. Applied electrical field resulted in an increase in the water acidity and ammonia basicity.
基金This work was supported by the National Natural Science Foundation of China (Grant Nos. 59790050, 29704009 and 59973024).
文摘Novel low dipole moment (μ) and large first hyperpolarizability (β) electrooptic chromophores have been designed based on the special characteristic of reversed dipole moment in the excited state of exocyclic double bond (ECDB) conjugated bridge by the optimization of the substituted method, and their electronic and second-order nonlinear optical properties have been theoretically investigated by employing the AM1/FF and ZINDO/S-CI approaches. By extending the conjugation length and optimizing the donor/acceptor strength, the oscillator strength of the excited transition that contributes to the molecular nonlinearity can be further enhanced. The designed chromophores possess a larger figure of merit (FOM) than that of 4-N,N-dimethylamino-4’-nitrostilbene (DANS), and lower (5 D) ground state dipole moment.Novel low dipole moment (μ) and large first hyperpolarizability (β) electrooptic chromophores have been designed based on the special characteristic of reversed dipole moment in the excited state
