共查询到13条相似文献,搜索用时 95 毫秒
1.
Time-dependent hybrid density functional theory in combination with Onsager reaction field model and super-molecular model has been applied to study solvent effects on the geometrical and electronic structures, as well as one/two-photon absorption properties, of 4-(N-(2-hydroxyethyl)-N-methyl)-amino-4'-nitroazobenzene. It is found that the short-range interaction has a large effect on the electronic structure of the solute molecule, namely, large red-shift of the maximum one-photon absorption is induced by hydrogen bonding. The solute molecule has a large two-photon absorption cross section, which is enhanced by the solvent effect. The computational results are in good agreement with measurements.[第一段] 相似文献
2.
The optical Kerr effect in a quantum disc is investigated with the density-matrix approach, most emphasis is devoted to the electron-phonon interactions on the optical Kerr effect. The numerical results are presented with characteristic parameters of a GaAs quantum disc. It is shown that the optical Kerr effect increases as the disc thickness D decreases. LO-phonons impose greater influence on the optical Kerr effect than SO-phonons. The smaller the disc thickness D, the sharper the peak, and the larger the peak intensity. When the disc thickness is greater than 30, the peak will disappear gradually. 相似文献
3.
The theoretical studies on the two-photon absorption properties of symmetric 1,4-bis{2-[4-(2- aryl) phenyl] vinyl }- 2,5-bisdialkoxyb enzenes 下载免费PDF全文
On the level of the time-dependent hybrid density functional theory, the one- and two-photon absorption properties of a series of symmetric 4-bis 2-[4-(2-ary12) phenyl]vinyl-2,5-bisdialkoxybenzenes are studied respectively utilizing the analytic response theory and the few-state model methods. The calculated results show that the planarity of the geometrical structure plays a great role in enhancing the linear and nonlinear optical abilities of the molecule. However the effect of the length of the chain linked to the π-centre on the optical property is very little. For the investigated compounds, the A–π–A type charge-transfer molecules display more superior one- and two-photon absorption characteristics than the D–π–D type ones. Furthermore, the two-photon absorption results by use of few-state model are generally consistent with those by analytic response theory, demonstrating the reliability of the few-state model for evaluating the two-photon absorption cross section. The numerical simulations are in good agreement in tendency with the available experimental measurements. 相似文献
4.
The electronic structures and optical properties of both the perfect CsI crystal and the crystal containing a pair of VCs^1- -V1^1+ are calculated using CASTEP code with the lattice structure optimized. The calculated results indicate that the optical symmetry of the CsI crystal coincides with the lattice structure geometry Vcs^1- - V1^1+ of the CsI crystal. The absorption spectrum of the CsI crystal containing a pair of Vcs^1- - V1^1+ also does not occur in the visible and near-ultraviolet range. It reveals that the existence of the pair of Vcs^1- - V1^1+ in CsI crystal has no visible effects on the optical properties of the CsI crystal. 相似文献
5.
Effects of N-doping concentration on the electronic structure and optical properties of N-doped β-Ga2O3 下载免费PDF全文
The electronic structures and the optical properties of N-doped β-Ga2O3 with different N-doping concentrations are studied using the first-principles method.We find that the N substituting O(1) atom is the most stable structure for the smallest formation energy.After N-doping,the charge density distribution significantly changes,and the acceptor impurity level is introduced above the valence band and intersects with the Fermi level.The impurity absorption edges appear to shift toward longer wavelengths with an increase in N-doping concentration.The complex refractive index shows metallic characteristics in the N-doped β-Ga2O3. 相似文献
6.
在杂化密度泛函理论(DFT/B3LYP)的水平上,研究了最新实验室合成的两个化合物分子9-乙烷基-3-{2-[4-2-吡啶-4-乙烯基苯]-乙烯基}-9氢咔唑(EPVPC)和9-十八烷基-3-{2-[4-2-吡啶-4-乙烯基苯]-乙烯基}-9氢咔唑(OPVPC)的非线性光学特性。理论结果与现有的实验测量结果符合得的较好。利用扩展的少态模型方法计算了分子的双光子吸收截面,结果表明三态模型可以很好地描述它们的最大双光子吸收截面。数值模拟显示这两个化合物都具有较大的双光子吸收截面,并且,在低频范围内,OPVPC分子比EPVPC分子显示出较强的双光子吸收特性。 相似文献
7.
The aggregation effects on the two-photon absorption properties of para-nitroaniline polymers by hydrogen-bond interactions 下载免费PDF全文
This paper has theoretically designed a series of
aggregate polymers on the basis of several para-nitroaniline
monomers by hydrogen-bond interactions. At the level of
time-dependent hybrid density functional theory, it has optimized
their geometrical structures and studied their two-photon absorption
(TPA) properties by using analytical response theory. The calculated
results exhibit that the aggregation effects not only bring out the
considerable red shift of the excited energies but also greatly
enhance the TPA intensities of the aggregate polymers in comparison
with the para-nitroaniline monomer. The aggregate configurations
also have an important influence on the TPA abilities of the
polymers; the trimer has the largest TPA cross section. The electron
transitions between the molecular orbits involving the strong TPA
excitations of the trimer are depicted to illuminate the
relationship between the intermolecular charge transfer and the TPA
property. 相似文献
8.
研究了一种新型双共轭链有机染料分子的双光子吸收(TPA)及其光功率限幅特性,实验研究了该有机染料的双光子吸收谱和光功率限幅曲线. 结果证实在浓度为1×10-2 mol/L的四氢呋喃(THF)溶液中,该有机染料在近红外区有宽达400nm的宽带非线性双光子吸收及光功率限幅特性. 它的双光子吸收谱存在三个峰,分别位于730,850和980nm,并且在850nm处有最大的TPA截面,为σ′2=25.9×10-47 cm4 sup>·s
关键词:
宽带
双光子吸收
光限幅
双共轭链有机分子 相似文献
9.
Observation of laser induced two-photon photoemission optogalvanic (TPPOG) effect from tungsten electrode in a discharge cell
using 564 nm radiation obtained from a pulsed dye laser is described. The magnitude of the POG signal is studied as a function
of laser energy under various discharge parameters. Competition between one-photon and two-photon processes has been observed
when nitrogen gas is used in the discharge cell. 相似文献
10.
The influence of rotational isomerism on the two-photon absorption(TPA) of FTC chromophores has been investigated using the quadratic response theory with the B3LYP functional.Eight rotamers induced by three rotatable single bonds in the molecule are fully optimized,and it is found that their conformational energies are nearly degenerate.Our calculations demonstrate that rotational isomerism has an important effect on the TPA cross sections.For a certain rotamer,the maximum TPA cross section is enhanced significantly.In addition,in the longer wavelength region,the rotational isomerism could lead to a large shift of the TPA position. 相似文献
11.
Theoretical studies on the one- and two-photon absorption properties of azulenylporphyrins and azulene-fused porphyrins 下载免费PDF全文
The electronic structures, one-photon absorption (OPA) and
two-photon absorption (TPA) properties of the azulenylporphyrins and
azulene-fused porphyrins have been comparatively studied by using
DFT/B3LYP/6-31G(d) and the ZINDO/SDCI method. With the number of
azulenyl groups increasing, the OPA wavelengths of all molecules are
red-shifted in 400--600~nm and the two-photon absorption cross section
is gradually enlarged. The azulene-fused structures facilitate an
expanding conjugated area and increasing TPA cross section. The
origin of TPA properties of studied compounds is studied with a
two-level model. In summary, the azulene-fused porphyrins exhibit
strong two-photon absorption. 相似文献
12.
以具有强双光子吸收特性的4,4′-二甲氨基二苯乙烯分子体系为研究对象,通过采用时域有限差分法和预估矫正法数值求解Maxwell-Bloch方程,模拟了飞秒脉冲在该分子介质中的传播过程,研究了含时电离对双光子吸收过程和光限幅行为的影响.研究结果表明,光电离使介质与光场的非线性相互作用减弱,同时自发辐射降低, 随着入射电场的增强,光电离对主脉冲演化有明显的影响.光电离使介质的光限幅失效行为减弱.随着光电离截面增加,光限幅的动力学窗口变宽,表明了光电离有利于增强介质的光限幅效应.在不同的传播距离处,脉冲传播呈现
关键词:
含时电离
双光子吸收
光限幅效应
超短脉冲激光 相似文献
13.
在密度泛函理论水平上,利用解析响应函数方法研究了以(4-{2-[4-(2-吡啶-4-乙烯基)-苯基]-乙烯基}-苯基)-胺为基本结构单元的单支、双支和三支共轭链有机分子的单光子和双光子吸收特性.计算结果表明,这三种有机分子都具有较大的线性和非线性吸收强度.在紫外-可见光区域,它们的单光子吸收谱都存在两个峰,这与实验结果符合较好.在近红外区域,多共轭链有机分子呈现出宽达300 nm的宽带双光子吸收,单支、双支和三支分子的最大双光子吸收截面比约为1.0∶2.3∶4.0,其中三支分子具有最大的双光子吸收截面101.73×10-48 cm4·s.从理论上进一步证实,增加分子的共轭链可有效提高分子的双光子吸收特性.同时还给出了电荷转移态的电荷迁移过程.
关键词:
双光子吸收
响应函数方法
多共轭链有机分子 相似文献