نتایج جستجو برای: ir vibrational frequencies
تعداد نتایج: 178821 فیلتر نتایج به سال:
1-Acetyl-3-(4-chlorophenyl)-5-(4-methylphenyl)-2-pyrazoline has been synthesized and characterized by elemental analysis, IR and X-ray single crystal diffraction. Density functional (DFT) calculations have been carried out for the title compound by using the B3LYP method at the 6-311G** basis set level. The calculated results show that the predicted geometry can reproduce well the structural pa...
In this study the molecular geometries, experimental vibrational and electronic absorption spectra and quantum chemical calculations of free dimethyl phenylphosphonite, (C8H11PO2), (with synonym, dimethoxyphenylphosphine or phenyldimethoxyphosphine) (Abbreviated as DMPP) and its [Cd(DMPP)].Cl2.H2O metal halide complex have been investigated by using elemental analysis, FT-IR, micro-Raman and UV...
Infrared (IR) band shifts of isolated vibrational transitions can serve as quantitative and directional probes of local electrostatic fields, due to the vibrational Stark effect. However, departures from the Stark model can arise when the probe participates in specific, chemical interactions, such as direct hydrogen bonding. We present a method to identify and correct for these departures based...
Quantitative vibrational difference spectroscopy of small signals requires techniques that minimize spectral noise. As simple modulation of the sample followed by signal demodulation is often problematic due to interference with the FT-IR Fourier frequencies, alternate methods are necessary. Using vibrational Stark spectroscopy as an example, the DC method involves alternating complete interfer...
The infrared spectroscopy (IR) of adsorbed hydrogen on a surface is an experimental technique used to analyze semiconductor surfaces. The hydrogen atoms are bonded to the surface dangling-bonds and the vibrational frequencies of the M–H bonds are very sensitive to the local chemical character at the surface. Usually the analysis of the results is based on the comparison with the IR spectra of m...
AB Initio Study of Molecular Struture, Energetic and Vibrational Spectra of (GaN)4 Nanosemiconductor
In recent years there has been considerable interest in the structures, energies and thermodynamics of(GaN)4 clusters and it is the subject of many experimental and theoretical studies because of theirfundamental importance in chemical and physical process. All calculation of this study is carried outby Gaussian 98. Geometry optimization for (GaN)4 nanocluster are be fulfilled at B3LYP, B1LYPan...
The infrared spectra of 1-methylthymine (1-MeT) in argon and nitrogen cryogenic matrices are presented, for the first time. The molecular structure, conformations, vibrational frequencies, infrared intensities and Raman scattering activities of 1-MeT have been calculated by the DFT(B3LYP), MP2 and HF methods using the D95V** basis set. The theoretically predicted intensity pattern of the IR and...
This paper describes an efficient and regioselective method for the synthesis of novel fluorinated spiro-heterocycles in excellent yield by cascade [5+1] double Michael addition reactions. The compounds 7,11-bis(4-fluorophenyl)-2,4-dimethyl- 2,4-diazaspiro[5.5] undecane-1,3,5,9-tetraone (3a) and 2,4-dimethyl-7,11-bis (4-(trifluoromethyl)phenyl)-2,4-diazaspiro[5.5]undecane-1,3,5,9-tetraone (3b) ...
Vibrational spectroscopy is frequently used to characterize nanoconfined liquids and probe the effect of the confining framework on the liquid structure and dynamics relative to the corresponding bulk fluid. However, it is still unclear what molecular-level information can be obtained from such measurements. In this paper, we address this question by using molecular dynamics (MD) simulations to...
In the present study, an attempt has been made to prepare an extract by the methanol from Toddalia asiatica leaf and it contains alkaloids. The molecular structure, functional groups, chemical bonds, etc has been analyzed with the help of IR, UV and MS spectrum. The Gaussian software has been used to estimate the theoretical values of vibrational frequencies of IR spectrum and for obtaining pos...
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