Based on the equilibrium structures from quantum mechanics AM1 method, employing INDO/CI method and the sum-over-state （SOS） formula, the one-photon absorption （OPA） and two-photon absorption （TPA） properties as...Based on the equilibrium structures from quantum mechanics AM1 method, employing INDO/CI method and the sum-over-state （SOS） formula, the one-photon absorption （OPA） and two-photon absorption （TPA） properties as well as the second hyperpolarizabilities were discussed in detail for a kind of PPV derivative poly 2-（9-phenylanthracen-10-yl）-1,4-phenylenevinylene （P1）. The results indicate that the two-photon cross section （3） increases with the increasing of the number of repeating segment （n）, however only a slight increase corresponds to the increasing of molecular weight when the repeating unit number arrives at a certain number. From this point of view, the TPA cross section values of P1 were extrapolated through the linear fit of 3 value vs. 1/n. The δ value of P1 is as high as 181 GM （1 GM=10^-50 cm^4·s·photon^-1）. Concerning the influence of pendent group and extension of π-conjugation on 3 values, another four oligomers P2, PPV, P1-1, and P2-1 were investigated for comparison. The calculation results reveal that the position and property of pendent group have great influence on the OPA and TPA properties. A most crucial role for relatively larger 3 value was played by the extension of π-conjugation.展开更多
The two-photon absorption induced lasing spectrum shows that the synthesized ASPBPh4, trans-4- [p- (N-methyl-N- (hydroxyethyl)amino) styryl]-N-methylpyridinium, has a distinct ef- ficiency of laser frequency up-conver...The two-photon absorption induced lasing spectrum shows that the synthesized ASPBPh4, trans-4- [p- (N-methyl-N- (hydroxyethyl)amino) styryl]-N-methylpyridinium, has a distinct ef- ficiency of laser frequency up-conversion. This nonlinear optical property of such a kind of com- pounds is related to two-photon absorption (TPA). In our work, we used the intermediate ne- glect of differential overlap (INDO) plus single-excitation configuration interaction (SCI) method to get the basic properties of the molecule, and calculated the second hyperpolarizability and the cross section of two-photon absorption by means of sum-over-state (SOS) expression. The rela- tionship between the structure and the properties is discussed.展开更多
The study of the linear and nonlinear optical properties of Zn Ge P2 based on density functional theory has been carried out. In order to get a more physical picture in the infrared region, terms which are considered ...The study of the linear and nonlinear optical properties of Zn Ge P2 based on density functional theory has been carried out. In order to get a more physical picture in the infrared region, terms which are considered as the phonon effect were added to the calculated refractive dispersion curves. The phonon-corrected calculation curves show excellent agreement with experimental refractive indexes, which gives a better comprehension of the linear optical proprieties in the transparent region. The static nonlinear optical susceptibility was investigated using approaches based on the ＂sum over states＂ and the2 n ＋ 1 theorem methods. Both of the results of these two methods reasonably coincided with the experimental results.展开更多
基金Project supported by the National Natural Science Foundation of China （No. 20373009）, the Specialized Research Fund for the Doctoral Program in Higher Education Institutions of the Ministry of Education of China （No. 20030183063） and Science Foundation for Young Teachers of Northeast Normal University （No. 20060311）.
文摘Based on the equilibrium structures from quantum mechanics AM1 method, employing INDO/CI method and the sum-over-state （SOS） formula, the one-photon absorption （OPA） and two-photon absorption （TPA） properties as well as the second hyperpolarizabilities were discussed in detail for a kind of PPV derivative poly 2-（9-phenylanthracen-10-yl）-1,4-phenylenevinylene （P1）. The results indicate that the two-photon cross section （3） increases with the increasing of the number of repeating segment （n）, however only a slight increase corresponds to the increasing of molecular weight when the repeating unit number arrives at a certain number. From this point of view, the TPA cross section values of P1 were extrapolated through the linear fit of 3 value vs. 1/n. The δ value of P1 is as high as 181 GM （1 GM=10^-50 cm^4·s·photon^-1）. Concerning the influence of pendent group and extension of π-conjugation on 3 values, another four oligomers P2, PPV, P1-1, and P2-1 were investigated for comparison. The calculation results reveal that the position and property of pendent group have great influence on the OPA and TPA properties. A most crucial role for relatively larger 3 value was played by the extension of π-conjugation.
文摘The two-photon absorption induced lasing spectrum shows that the synthesized ASPBPh4, trans-4- [p- (N-methyl-N- (hydroxyethyl)amino) styryl]-N-methylpyridinium, has a distinct ef- ficiency of laser frequency up-conversion. This nonlinear optical property of such a kind of com- pounds is related to two-photon absorption (TPA). In our work, we used the intermediate ne- glect of differential overlap (INDO) plus single-excitation configuration interaction (SCI) method to get the basic properties of the molecule, and calculated the second hyperpolarizability and the cross section of two-photon absorption by means of sum-over-state (SOS) expression. The rela- tionship between the structure and the properties is discussed.
基金supported by the National Natural Science Foundation of China(Grant No.51202250)the Knowledge Innovation Program of the Chinese Academy of Sciences(Grant No.13J131211)
文摘The study of the linear and nonlinear optical properties of Zn Ge P2 based on density functional theory has been carried out. In order to get a more physical picture in the infrared region, terms which are considered as the phonon effect were added to the calculated refractive dispersion curves. The phonon-corrected calculation curves show excellent agreement with experimental refractive indexes, which gives a better comprehension of the linear optical proprieties in the transparent region. The static nonlinear optical susceptibility was investigated using approaches based on the ＂sum over states＂ and the2 n ＋ 1 theorem methods. Both of the results of these two methods reasonably coincided with the experimental results.
