Photochromism of palmitoylamide-substituted indoline spiropyrans

A comparative spectral-kinetic and luminescent study of photochromic transformations of two palmitoylamide-substituted indoline spiropyrans was performed in solvents with various polarities and polyvinylbutyral binding and amorphous layers. The compounds were found to be photochromic and form aggregates of two types in addition to the monomeric merocyanine form under the action of UV irradiation. The formation of these photoproducts depended on solvent polarity and the state of aggregation of the substances.     

Interpretation of vibrational spectra of a closed form of indoline spirophenanthroxazine

We have measured IR and Raman spectra of molecules of a closed form of the photochromic compound indolinespirophenanthroxazine. Using the density-functional method, we have optimized the structures of the closed and open forms of this molecule and calculated its normal vibrations. Based on these calculations, we propose an interpretation of the obtained vibrational spectra. We have determined the spectral range of manifestation, 700–900 cm^?1, and have found wavenumbers of normal vibrations through which the spiro structure of the indolinespirophenanthroxazine molecule in an excited state is likely to be rearranged into a merocyanine structure.     

Intramolecular heavy atom effect on the polarization of phosphorescence of phenylacetylene

Phosphorescence spectra, both unpolarized quasilinear in a Shpolskii matrix and polarized in a rigid glass matrix, have been measured for seven monohalogen ring substituted phenylacetylenes. The vibrational analyses indicate the presence of two subspectra, labelled I and II. Subspectrum I involves transitions from T₁ to totally symmetric vibrational levels of S₀ while Subspectrum II refers to transitions from T₁ to b₁ (out-of- plane) vibrational levels of S₀. In the parent phenylacetylene, 90% of the intensity is attributed to subspectrum I; in the halo derivatives, the percentage of subspectrum II increases with mass of halogen. The polarization results show an enhancement of 0,0 in plane polarization contributions with heavy atom. Subspectrum I's out-of-plane polarized contribution is accounted for by T₁ mixing with σπ states, while the in plane polarized part is rationalized by direct spin-orbit coupling with ππ¹ states via three-center integrals and by 2nd order Herzberg-Teller spin-orbit coupling. Subspectrum II arises from 1st order Herzberg-Teller spin-orbit coupling.     

Interpretation of level-anticrossing phenomena in phosphorescence and optical nuclear polarization in organic crystals

Level-anticrossing (LAC) phenomena in electronic states of molecules in organic crystals are described with a density matrix formalism. A condition for the observability of LAC signals in phosphorescence and ONP is derived. The validity of these predictions is tested at quadrupole satellite positions in the LAC spectra. As a consequence of the full density matrix treatment, off-diagonal damping terms Γ _mn = T ₂ ^-1(mn) are introduced. These turned out to be essential for the interpretation of the vanishing of experimentally observed LAC signals at higher order satellite positions. If T ₂ equals the lifetime τ of the triplet state, earlier predictions based on kinetic arguments evolve as a limiting case of the present theory. The quadrupole satellite signals can be described properly by the density matrix formalism and there is no need for the introduction of an additional cross-relaxation mechanism.     

IR spectrum of the closed form of indolinospironaphthooxazine

IR absorption spectra of indolinospironaphthooxazine (ISNO) are presented. The geometric structure and normal coordinates of the ISNO molecule have been calculated using a quantum mechanical DFT method. The IR spectrum of ISNO in its original spiro form has been interpreted for the first time. Four normal modes in the range 800–1200 cm^–1 with the largest amplitudes of C_spiro–O bond change are identified. The excited ISNO molecule spiro form may experience photoconversion to the merocyanine form through them.     

Skew aberration: a form of polarization aberration

We define a new class of aberration, skew aberration, which is a component of polarization aberration. Skew aberration is an intrinsic rotation of polarization states due to the geometric transformation of local coordinates, independent of coatings and interface polarization. Skew aberration in a radially symmetric system has the form of a circular retardance tilt plus coma aberration. Skew aberration causes undesired polarization distribution in the exit pupil. We demonstrate statistics on skew aberration of 2383 optical systems described in Code V's U.S. patent library [Code V Version 10.3 (Synopsys, 2011), pp. 22-24]; the mean skew aberration is 0.89° and the standard deviation is 1.37°. The maximum skew aberration found is 17.45° and the minimum is -11.33°. U.S. patent 2,896,506, which has ±7.01° of skew aberration, is analyzed in detail. Skew aberration should be of concern in microlithography optics and other high NA and large field of view optical systems.     

Dichroism of absorption by impurity molecules with internal rotation in nematic liquid crystals

Expressions are obtained for the components of the permittivity tensor in the optical region for a nematic liquid crystal with impurity molecules having the internal rotation conformational degree of freedom. The dependence of the intensity and dichroism of the impurity absorption bands in isotropic and nematic phases on the parameters of conformational, orientation, and mixed conformation-orientation orders of molecules is found. The influence of the mutual correlation of conformational and orientation degrees of freedom of molecules on these parameters is studied. The dependence of the oscillator strengths of molecular transitions on the phase state of a medium and the orientation order of the impurity subsystem is analyzed. The self-consistent nature of molecular, structural, and spectral changes upon the nematic-isotropic liquid phase transition is demonstrated.     

Pade approximants and closed form solutions of the KdV and MKdV equations

The closed form solutions of the Kortewegde Vries (KdV) and modified MKdV equations which are obtainable by inverse scattering or Hirota's method are found to be Pade approximants to the formal series which results from iterating particular solutions of the linearized equation.     

电子自旋偏振度及其弛豫过程的飞秒激光吸收光谱研究

基于二能级体系的速率方程，获得了非完全初始自旋偏振极化条件下的自旋偏振向上和向下 载流子布居弛豫的解析解. 基于小信号近似，给出了左、右旋圆偏振探测光的饱和吸收变化 的表达式. 此表达式中含有电子布居的初始自旋偏振度参数，因而用此表达式拟合实验数据 能够直接获取电子布居的初始自旋偏振度，而电子布居的初始自旋偏振度在自旋偏振输运研 究中是一个非常重要的关键参数. 实验获得了GaAs/AlGaAs多量子阱结构中光注入电子布居 的初始自旋偏振度及其弛豫时间常数. 关键词： 圆偏振抽运_探测技术 电子自旋偏振度 自旋偏振弛豫 GaAs量子阱