نتایج جستجو برای: ir spectra
تعداد نتایج: 171670 فیلتر نتایج به سال:
Infrared spectra of complexes of small vanadium oxide clusters with ethene are determined using infrared multiple photon dissociation (IR-MPD) spectroscopy in the range of 550-1850 cm-1. The structures of the complexes have been identified by comparison of the experimental spectra with the harmonic vibrational frequencies and corresponding IR intensities of possible isomers calculated with DFT ...
Syntheses of organometallic initiators were conducted under a nitrogen atmosphere using standard Schlenk techniques. All reagents were of commercial grade and obtained from Sigma-Aldrich Co.. Solvents and the propionic acid used for the preparation of initiators were carefully dried and distilled under nitrogen atmosphere prior to use. TEMPO was sublimated and stored under nitrogen atmosphere. ...
We report spectroscopy of clusters of guanine base pairs with one and two water molecules. We recorded the vibronic spectra of the mass-selected GG(H2O) and GG(H2O)2 clusters using resonant two photon ionization (R2PI) and we used IR-UV double resonance spectroscopy to obtain ground state IR spectra of these clusters. We found that a single water molecule stabilizes one of two structures we had...
UV irradiation of 1,3-dimethyluracil in ice-matrix yields four dimeric dimethyluracils (2 c) — (5 c) , which could be isolated by preparative thin-layer chromatography. Attemps for structure elucidation of these four dimers by UV, IR, NMR and mass-spectrometric methodes pointed out, that only NMR-spectra give structural evidences; by IR — not by mass-spectra — certain identification of dimers i...
Direct determination of the adsorbed amounts of surfactants on AgI by IR-spectroscopy is described. The adsorbed quantities are determined from the relationship between the intensities of the characteristic bands in IR-spectra of standard samples and the samples with adsorbed surfactants. The samples for IR-measurements are in the form of patterns consisting of AgI separated from the systems. T...
Fourier-transform infrared (FT-IR) microspectroscopic mapping can be used to distinguish between different tissue structures, and to increase the image contrast between normal and cancerous regions of a given tissue sample. This study demonstrates the biochemical changes associated with a consistent link between cancerous tissue and various molecular changes in the IR spectra of human pancreati...
Pentacoordinated copper(II) complexes were synthesized from tetradentate ligand N,N-bis (2-methyl-N-methylbenzimidazolyl)hexanediamide. Characterization has been done on the basis of elemental analysis, electronic spectra, IR studies, conductance data, magnetic properties, EPR and x-ray studies for the complexes. From analytical data, the stoichiometry of the complexes has been found to be 1:1 ...
We present the IR-UV double resonance spectrum of guanine monohydrate in the region 3100 cm(-1) to 3800 cm(-1) along with the energies and frequencies of these structures calculated at the non-empirical correlated ab initio RI-MP2/cc-pVDZ level. We assign the structures of guanine-water clusters by comparing the experimental spectra with the ab initio calculations and with the IR spectra of the...
The IR and Raman spectra of the title compound have been recorded and analyzed. The harmonic vibrational wavenumbers were calculated theoretically using Gaussian09 software package. Calculations were performed by HF and DFT levels using the standard 6-31G* basis sets. The data obtained from vibrational wavenumber calculations are used to assign vibrational bands found in the IR and Raman spectr...
We report low-energy locally stable structures for the clusters Si 20 and Si21 . The structures were obtained by performing geometry optimizations within the local density approximation. Our calculated binding energies for these clusters are larger than any previously reported for this size regime. To aid in the experimental identification of the structures, we have computed the full vibrationa...
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