Spectroscopic and proton-acceptor properties of biologically active molecules of benzoic acid and its derivatives

We have measured the absorption, fluorescence, fluorescence excitation spectra, fluorescence quantum yields, and IR Fourier-transform spectra of aromatic acids in solutions. We have considered spectroscopic particular features of benzoic acid, its hydroxylated and methoxylated derivatives. Using quantumchemistry methods, we have calculated and interpreted electronic spectra. Data of calculations have been compared with experimental results. We have ascertained the main channels and mechanisms of photophysical relaxation processes in the molecules under study. Proton-acceptor properties of molecules of aromatic acids have been evaluated. We have analyzed in detail mechanisms by which hydrogen bonds are formed, intramolecular charge redistribution is realized, and the electron density of oxygen atoms changes. Spectroscopic indications of participation of oxygen-containing groups in intramolecular interactions and in intermolecular interactions with the formation of cyclic dimers have been revealed.     

Spectroscopic properties of SbH

Relativistic configuration interaction calculations which include spin-orbit interaction are carried out for nine low-lying ω-ω states and four λ-s states. Spectroscopic properties of six bound ω-ω states are reported. These calculations not only enable assignment of the experimentally observed X₁, X₂, A₁, A₂, and B states but also predict the properties of other electronic states (0⁺(II), 0⁺(IV), 2, 2(II), 1(II), 0⁻) which are yet to be observed. The dissociation energy of SbH is predicted to be 2.7 ± 0.2 eV.     

Spectroscopic properties of fission isomers

Our present understanding of the spectroscopic properties of fission isomers is discussed. Recent progress has been achieved by applying newly developed and improved experimental techniques such as the charge plunger method and the recoil shadow technique to measure quadrupole moments, moments of inertia, and spins of fission isomeric states. The data establish the evidence for shape isomerism in the actinide region and a second minimum in the fission potential.     

Spectroscopic properties of A baryons

The resonance state of the A baryon,which exists in four isospin(I = 3/2)states,has been studied using the hypercentral constituent quark model(hCQM)with a simp...     

LiCl~–阴离子的光谱性质和跃迁性质

采用多参考组态相互作用方法结合全电子基组计算了LiCl~-阴离子5个电子态(X~2Σ~+,A~2Π,B~2Σ~+,3~2Σ~+,2~2Π)的电子结构.为了得到精确的光谱常数,计算中考虑了Davidson修正、芯-价电子关联效应和自旋-轨道稱合效应.拟合得到各电子态的光谱常数、分子常数、自发辐射速率和自发辐射寿命.基态的光谱常数与实验值和其他理论值符合较好,同时报道了LiCl~-阴离子激发态的光谱常数以及其到基态的跃迁性质.计算结果表明A~2Π?X~2Σ~+跃迁具有高对角分布的弗兰克-康登因子f₀₀,第一激发态A~2Π有较短的自发辐射寿命.构造A~2Π(v’)? X~2Σ~+(v)准循环跃迁进行激光冷却LiCl~-阴离子需要一束主激光和两束抽运激光.以上结果预测了激光冷却LiCl~-阴离子是可行的.     

Spectral study of modified natural clinoptilolite with pharmacologically active escin and horse chestnut extract

The aim of this study was preparation of modified forms of natural zeolite of the clinoptilolite type with different content of pharmacologically active natural substances escin and horse chestnut extract and their characterization by infrared spectroscopy, fluorescence spectroscopy, thermal analysis, röntgen diffraction powder technique, and determination of the surface areas and the pore volumes by low-temperature adsorption of nitrogen. Escin and horse chestnut extract have also been investigated by atomic force microscopy. The analyses confirmed the presence of escin and horse chestnut extract in the modified zeolitic products. The modified forms of natural zeolite of the clinoptilolite type with low content of escin and horse chestnut extract have been used for preliminary in vitro study of their anticancer effects on cancer cell lines by an in vitro colorimetric assay for assessing cell viability. To understand the growth inhibitory effects, the human cervical carcinoma cells, human T-cell acute lymphoblastic leukemia, breast cancer cells, human alveolar basal epithelial cells, and human breast adenocarcinoma cells were treated with various doses of the modified zeolitic products. The modified forms were the most effective in adenocarcinomic human alveolar basal epithelial cells.     

Spectroscopic properties of alexandrite crystals II

Several aspects of the optical spectroscopic properties of alexandrite crystals not previously investigated are reported here. For Cr³⁺ ions occupying the Al³⁺ lattice sites with mirror symmetry in BeAl₂O₄, the positions of the zero-phonon lines for absorption transitions to the ²T_1g and ⁴T_2g levels are identified, and vibronic transition peaks in the fluorescence spectrum are compared to transitions appearing in the Raman spectrum and Stokes excitation spectrum. In addition, the effects of radiation trapping are shown to lengthen the fluorescence lifetime of the ²E_g - ⁴A_2g transition for ions in these sites at low temperatures. For Cr³⁺ ions occupying the Al³⁺ lattice with inversion symmetry, the ground state splitting of the ²E_g - ⁴A_2g transition is reported and the decrease of the fluorescence lifetime with temperature is shown to be due to the increase in vibronic emission probability as well as increased probability of direct radiationless decay.     

Spectroscopic properties of transition elements and their related magnetic properties

Optical and magnetic properties of transition elements (nd^N and nf^N ions) are re-analysed. The aim of this work is to see how far a unique set of phenomenological parameters, those introduced by crystal-ligand field theory described on the ∣αSLJM> kets, can describe the experimental data.     

一种新型掺铒碲酸盐玻璃的光谱性质研究

研究了一种新型掺Er³⁺碲酸盐玻璃的光谱性质；应用Judd-Ofelt理论计算了碲 酸盐玻璃中Er³⁺离子的强度参数Ω(Ω₂=479×10^-20 cm²,Ω₄= 152×10^-20cm²,Ω₆=066×10^-20cm2)，计算了离子的自发跃迁概 率，荧光分支比；应用McCumber理论计算了Er³⁺的受激发射截面(σ_{e=1040×1 0^-21cm²)，Er³⁺离子⁴I13/ 2→⁴I15/2发射谱的 荧光半高宽(FWHM=655nm)及各能级的荧光寿命(⁴I13/2 能级为τrad =399ms)；比较了不同基质玻璃以及不同类型碲酸盐玻璃中Er³⁺离子的光谱 特性， 结果表明该掺铒碲酸盐玻璃具有更好的光谱性能，更适合于掺Er³⁺光纤放大 器实现宽带和高增益放大. 关键词： 碲酸盐玻璃 光谱性质 Judd-Ofelt理论}     

Spectroscopic properties of neodymium-doped tellurite glass fiber

Nd3+-doped tellurite glass and a single mode tellurite glass fiber with a core diameter of 8 μm were prepared in this work. The 1.33-μm emission from the 4F3/2→4I13/2 transition of Nd3+ with a spectral bandwidth of 55 nm in tellurite glass fiber is observed.The lifetime of 164μs of 4F3/2 level and quantum efficiency of about 100 ％ are obtained.     

Spectroscopic properties of DNA-acridine orange biopolymer films

Using electronic absorption, luminescence, and vibrational spectroscopy, we study the properties of DNA-acridine orange biopolymer films. The conformational structure of DNA molecules in the film is examined at different levels of the relative humidity, and the state of dye molecules incorporated into the structure of the biopolymer is estimated. These structures were formed according to the “guest-host” principle and the dye molecule acts as the “guest” and the “host” is the intercalative DNA binding sites. In such system dye molecules demonstrate high luminescence capability and are the uniform optical centers and their fluorescence spectrum doesn’t depend on excitation wavelength.     

Spectroscopic constants and molecular properties of diatomic carbides

Spectroscopic constants and molecular properties of the diatomic carbides BeC, BC⁺, BC, NaC, and MgC in their ground states have been studied in detail using hybrid HF/DF B3LYP method. The effect of basis set on spectroscopic constants and molecular properties have been studied systematically with the improvement of the quality of the basis set from cc-pVDZ to cc-pV5Z. These results have been extrapolated to the complete basis set (CBS) limit. The spectroscopic constants of these diatomic carbides agree very well with the experimental and theoretical results wherever available for comparison. Most of the spectroscopic constants of BC, BC⁺, and NaC and the molecular properties of these carbides are first reported.     

Spectroscopic properties of CF+ calculated by SCEP-CEPA

The near-equilibrium potential and electric dipole moment curve of CF⁺ has been calculated by SCEP-CEPA using a basis set of 66 contracted Gaussian-type orbitals. The calculated spectroscopic constants are in good agreement with very recent experimental values. The dipole moment of ¹²C¹⁹F⁺ in the vibrational ground state is calculated to be −1.163 D and the absorption band strength of the 1-0 vibrational transition is 835 atm⁻¹ cm⁻² at 298 K.