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Showing 1 to 20 of 59 for “"Vibrational Frequencies"”.
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Effects of shear deformations on the vibrational frequencies of wide-flanged structures
The well-known Timoshenko beam equations (which include transverse shear deformation and rotary inertia effects) are extended for a wide-flanged structure to include the additional shear lag deformation of the flanges; thus, cross-sections of the beam are allowed to distort instead of remaining …
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Theoretical Investigation of the Structure and Vibrational Frequencies of Water and Methanol Complexes
… effect on retention. Therefore, structure and frequencies of complexes of these solvent molecules have been studied from a theoretical perspective as a first step in this direction. Specifically, cluster structures have been optimized at the RHF and MP2 levels in various flexible basis sets and …
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Theoretical Prediction of Electronically Excited States and Vibrational Frequencies of Interstellar and Planetary Radicals, Anions, and Cations
… and also predicts the gas phase fundamental vibrational frequencies of the cis and trans-HOCO radicals, as well as the cis-HOCO anion. First, open-shell coupled cluster methods of singles and doubles (CCSD) and singles and doubles with triples-inclusion (CC3) are tested on the C₂H and C₄H …
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Accurate Computation Of Molecular Properties From Novel Applications Of Quantum Mechanical Wavefunction Methods
… technique has been extended to compute harmonic vibrational frequencies of clusters. Applying this methodology to small hydrogen-bonded clusters demonstrates that this approach yields both optimized geometries and harmonic vibrational frequencies in excellent agreement with the "gold standard" of …
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SPECTROSCOPIC CHARACTERIZATIONS OF THE COMPOUND II INTERMEDIATE OF SOYBEAN PEROXIDASE FROM SOYBEAN SEED COATINGS
… However, the focus of this study was on the vibrational region of the resonance Raman spectra from 900 to 500cm-1 where the FeIV=O stretching frequencies for heme compound II intermediates are expected. Several pH and pD (deuterium substitution) samples of the soybean peroxidase were analyzed …
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Spectroscopic and theoretical studies of small molecules.
… v1-v4, allowing the determination of revised vibrational frequencies and rotational parameters. Perturbations found to be present in all bands were elucidated and identified with the aid of H2C13CO, H213CCO and D2CCO isotopic species. Approximate analyses on these species also permitted the …
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Ligand isotope vibrational studies of metal(II) complexes with particular reference to heterocyclic N-oxides
A critical examination of the characteristic N-O vibrational frequencies of aromatic N-oxides questions the widely held assignment of αN-O (840cm⁻¹) and YN-O (47oon- 1). The present investigation supports the assignments of αN-O (470cm⁻¹) and γN-O (280cm⁻¹), with the assignment of the band at …
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ΦΑΣΜΑΤΟΣΚΟΠΙΚΗ ΜΕΛΕΤΗ ΑΕΡΙΩΝ ΣΥΜΠΛΟΚΩΝ ΣΕ ΥΨΗΛΕΣ ΘΕΡΜΟΚΡΑΣΙΕΣ ΣΕ ΣΥΣΤΗΜΑΤΑ ΧΛΩΡΙΟΥΧΩΝ ΑΛΑΤΩΝ ΤΩΝ ΣΙΔΗΡΟΥ, ΧΡΥΣΟΥ ΚΑΙ ΑΛΟΥΜΙΝΙΟΥ
… (III) CHLORIDE-ALUMINUM CHLORIDE SYSTEM, THE VIBRATIONAL FREQUENCIES OF THE FE2CL6(9), FECL3(9) AND FEA MOLECULES WERE MEASURED FROM THE RAMAN SPECTRA. VIBRATIONAL ANALYSIS WAS PERFORMED FOR THE ABOVE MOLECULES BY MEANS OF "NORMAL COORDINATE ANALYSIS". THETHERMODYNAMIC FUNCTIONS OF ALL THE …
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Effect of air on vibration of structures
… results to determine how air modifies the vibrational behavior of structures. This work may help in determining the characteristics of structural vibrations — from acoustic behavior to earthquake response - in practical buildings. The work consists of several primary components: derivation …
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Dynamics of hydrogen and low concentration carbon on Au-Ni(111) surface alloys
… binding energy of 63 kcal/mol and characteristic vibrational frequencies of 970 and 1170 cm-¹. Hydrogen atoms bind relatively weakly to threefold hollow sites consisting of two Ni atoms and one Au atom, with a binding energy of 55 kcal/mol and characteristic vibrational frequencies of 820 and 1050 …
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Developing a disturbance source characterization technique for small satellite applications
… characterize we mean estimate disturbance source vibrational frequencies, and by candidate sources we mean sources previously determined with the ability to induce micro-vibrations. This framework centers on the operation of distributed sensors, and we present a set of components capable of …
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A Computational Study on 18+δ Organometallics
… bond distances, natural atomic charges and IR vibrational frequencies were compared with the available experimental parameters. The differences between the 19- and 18-electron systems have been analyzed. The results reveal that the 19th electron is mostly distributed over the ligand of …
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Comparison of Calculated Normal Mode Molecular Vibrations with Experimental Gas-Phase Infrared Spectroscopy
<p>Computational vibrational spectroscopy serves as an important tool in the interpretation of experimental infrared (IR) spectra. Analysis of computational results provides a perspective over broader wavelength ranges and at higher precision. Although there are issues regarding accuracy, this can …
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Quartic Force Fields for Electronically Excited States of Interstellar Molecules
… spectroscopic accuracy (±1 cm−1) for fundamental vibrational frequencies. A method for extending QFFs to variationally inaccessible electronically excited states is presented herein using equation-of-motion (EOM) coupled cluster theory. The new EOM-based QFF is tested against the traditional QFF …
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SEMICLASSICAL VIBRATIONAL SPECTROSCOPY BEYOND POWER SPECTRA
… of classical trajectories. Traditionally, SC vibrational spectroscopy has focused on the calculation of power spectra, which provide vibrational energy levels but do not directly reproduce experimental IR intensities. This Ph.D. thesis presents the development of a new semiclassical approach …
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Kinetics of HO2 abstraction of H atoms from hydrocarbons and thermochemical properties of urethane monomers and radicals
… analyzed in this study. Molecular structures and vibrational frequencies are determined at the B3LYP/6-3111G(d,p) density functional level. The S _{298} and C_p(T) values (300<=T/K<=1500) from vibrational, translational, and external rotational contributions are calculated using statistical …
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Computational Studies on Group 14 Elements (C, Si and Ge) in Organometallic and Biological Compounds.
… scale factors for computed harmonic CºO vibrational frequencies for 31 organometallic complexes have been determined at the HF and B3LYP levels. The scaled B3LYP frequencies exhibit a greater reliability than do HF frequencies. Experimental data have shown that Si/Ge-substituted …
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Noncovalent Interactions Involving Microsolvated Networks Of Trimethylamine N-Oxide
… osmolyte trimethylamine N-oxide (TMAO). Vibrational spectroscopy, in this case Raman spectroscopy, is used to interpret the effects of noncovalent interactions by solvation with select hydrogen bond donors such as water, methanol, ethanol and ethylene glycol in the form of slight changes …
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Multiphoton ionization and photoelectron spectroscopy of hydrogen iodide with fixed wavelength and tunable laser sources
… of $\sim$10$\sp{12}$ W/cm$\sp2,$ reveal clear vibrational progressions associated with the $X\sp2\Pi$ spin-orbit split ion states following three- and four-photon ionization. Analysis of these spectra yields vibrational frequencies that differ from those from single photon experiments of …
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A trajectory-based approach to modeling nonlinear infrared spectra : interrogating strong hydrogen bonds and proton transfer
… for spectroscopic variables, here the vibrational frequencies and transition dipole moments, and use these as inputs to calculate the system response to an applied electric field. This method identifies key dynamical variables, treats these stochastically, and then constructs …
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