نتایج جستجو برای: ir vibrational frequencies
تعداد نتایج: 178821 فیلتر نتایج به سال:
The protonated HCl dimer and trimer complexes were prepared by pulsed discharges in supersonic expansions of helium or argon doped with hydrogen. ions mass selected a reflectron time-of-flight spectrometer investigated photodissociation spectroscopy the IR near-IR regions. Anharmonic vibrational frequencies computed VPT2 at MP2/cc-pVTZ level theory. Cl–H stretching fundamentals overtones measur...
The spectroscopic properties of the 2,2,6,6-tetramethyl-piperidine-1-oxyl (TEMPO) radicalderivatives of the fullerene (C60) were theoretically investigated. The ground state optimizedstructures of the radical adducts of the fullerene were calculated by using DFT (B3LYP) with 6-31G(d) level. It was concluded that a 6-6 ring junction of C60 moiety generally covalently links to thepiperidine ring ...
We present a combined theoretical and experimental study of ultrafast wave-packet dynamics in the dissociative ionization of H_{2} molecules as a result of irradiation with an extreme-ultraviolet (XUV) pulse followed by an infrared (IR) pulse. In experiments where the duration of both the XUV and IR pulses are shorter than the vibrational period of H_{2};{+}, dephasing and rephasing of the vibr...
In a recent work (J. Phys. Chem. C 2016, 120, 3350-3359), we have introduced the concept of surface-enhanced, two-dimensional attenuated total reflectance (2D ATR IR) spectroscopy with modest enhancement factors (<50) using small plasmonic noble metal nanoparticles at solid-liquid interfaces. Here, we show that employment of almost continuous noble metal layers results in significantly stronger...
We demonstrate a correlation between how an IR-active vibrational mode responds to temperature changes and how it responds to crystallinity differences. Infrared (IR) spectroscopy was used to track changes in carbonate-related vibrational modes in three different CaCO3 polymorphs (calcite, aragonite, and vaterite) and CaMg(CO3)2 (dolomite) during heating. Of the three characteristic IR-active c...
We report experimental spectra in the mid-infrared (IR) and near-IR for a series of dibenzoacenes isolated in Ar matrices. The experiments are supported by Density Functional Theory (DFT) and Time-Dependent DFT (TD-DFT) calculations with both vibrational and electronic transitions studied. For the neutrals, we find good agreement between the experimental and B3LYP and BP86 results for all speci...
The kinetics of the development first-order diffuse structural phase transition in monodisperse samples tetracosane C 24 H 50 was studied by FTIR spectroscopy. temperature dependences frequencies and intensities C-H-stretching vibrations spectral region ν=2800-3000 cm -1 were for 4 different modes methylene CH 2 trans sequences main chain corresponding to end methyl 3 -groups. Specific changes ...
We present R2PI, IR–UV and UV–UV double resonance measurements of the guanine–cytosine (G–C) dimer formed in a supersonic jet. We show that there is only one isomer of G–C in the investigated wavelength range from 33200 to 34100 cm . We assigned the observed G–C isomer to a specific structure, based on comparisons of the IR spectra of the G and C monomers with the G–C dimer in the range of the ...
The Criegee intermediates are carbonyl oxides postulated to play key roles in the reactions of ozone with unsaturated hydrocarbons; these reactions constitute an important mechanism for the removal of unsaturated hydrocarbons and for the production of OH in the atmosphere. Here, we report the transient infrared (IR) absorption spectrum of the simplest Criegee intermediate CH2OO, produced from C...
The syntheses of new tetraaza macrocyclic compounds of variable ring sizes by non-template methods and their characterization with the help of elemental analysis and spectroscopic techniques (FT-IR, 1 H-NMR, and 13 C-NMR) have been reported in detail. The vibrational frequencies determined experimentally are compared with those obtained theoretically from density functional theory (DFT) and Har...
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