نتایج جستجو برای: vibrational spectra

تعداد نتایج: 123243  

Journal: :Physical chemistry chemical physics : PCCP 2009
Nighat Kausar Trevor J Dines Babur Z Chowdhry Bruce D Alexander

Solid state IR and Raman as well as aqueous solution state Raman spectra are reported for the linear di-amino acid peptide L-aspartyl-L-glutamic acid (L-Asp-L-Glu); the solution state Raman spectrum has also been obtained for the N,O-deuterated derivative. SCF-DFT calculations at the B3-LYP/cc-pVDZ level established that the structure and vibrational spectra of L-Asp-L-Glu can be interpreted us...

Journal: :The journal of physical chemistry. A 2009
Lucas Koziol Vadim A Mozhayskiy Bastiaan J Braams Joel M Bowman Anna I Krylov

Photoelectron spectra of the cis and trans isomers of HCOH were computed using vibrational wave functions calculated by diagonalizing the Watson Hamiltonian, including up to four mode couplings. The full-dimensional CCSD(T)/cc-pVTZ potential energy surfaces were employed in the calculation. Photoionization induces significant changes in equilibrium structures, which results in long progressions...

Journal: :The Journal of chemical physics 2011
Etienne Garand Daniel M Neumark

High-resolution photoelectron spectra of RgS(-) (Rg = Ne, Ar, and Kr) were obtained using slow electron velocity-map imaging (SEVI). The SEVI spectra reveal well-resolved vibrational transitions between multiple spin-orbit states of RgS(-) and RgS, both of which are open-shell species. Detailed assignments are made by comparison with theoretical simulations based on high level ab initio calcula...

Journal: :Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy 2007
Piotr M Wojciechowski Danuta Michalska

The theoretical IR and Raman spectra of para-halogenoanilines, 4-XC(6)H(4)NH(2) (X=F, Cl and Br) were calculated by using the density functional B3LYP method with the 6-311++G(df,pd) basis set. The theoretical spectra show very good agreement with experiment. The rigorous normal coordinate analyses have been performed, and the detailed vibrational assignment has been made on the basis of the ca...

Journal: :Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy 2007
Alicia H Jubert María L Alegre Reinaldo Pis Diez Alicia B Pomilio Víctor D Szewczuk

NMR, infrared and Raman vibrational spectra of alpha-cypermethrin have been measured at room temperature. Infrared spectra were also recorded to low temperature. The spectra were analyzed by means of ab initio calculations. The conformational space of both enantiomers and some rotamers A, B and C of alpha-cypermethrin has been scanned using molecular dynamics and complemented with functional de...

Journal: :Physical chemistry chemical physics : PCCP 2012
Jörg Koßmann Christof Hättig

We investigate defects in bulk zinc oxide by performing embedded cluster calculations within the density functional theory using the PBE functional. We obtain and discuss equilibrium structures and vibrational spectra of interstitial hydrogen species and of hydrogen complexes at zinc vacancies and at substitutional atoms like copper, beryllium, manganese and calcium in zinc positions. All of th...

2005
C. Ratsch G. Meijer

The far-infrared vibrational spectra for charged vanadium clusters as well as charged and neutral niobium clusters have been measured size specifically using farinfrared multiple photon dissociation. The ground state energy and vibrational spectra of a large number of stable and metastable structures for each of these sizes and systems have also been calculated using densityfunctional theory (D...

2003
P.Udhayakala A.Jayanthi T. V. Rajendiran S. Gunasekaran

The FT-IR (4000-400 cm) and FTRaman (4000-100 cm) spectra of 2-chloro-4-nitroaniline (2Cl4NA) have been recorded using Bruker IFS 66 V spectrometer. An ab initio HF(HF/6-311G(d,p) and DFT(B3LYP/6-311G(d,p)) calculations have been performed giving energies, optimized structures, harmonic vibrational frequencies,IR intensities and Raman activities. The study is extended to the HOMO LUMO analysis ...

2006

The vibrational motion of a molecule is quantized and the resulting energy level spacings give rise to transitions in the mid-IR portion of the electromagnetic spectrum (4000 to ca. 400 cm). As you know from study of the diatomic harmonic oscillator, the energies (or wavenumber positions, cm) of these transitions are related to the bond strength (force constant), bond length, and atomic masses ...

Journal: :The Journal of chemical physics 2006
R Z Martínez Kevin K Lehmann Stuart Carter

This article describes the analysis and interpretation of rovibrational spectra involving highly excited vibrational states in the molecule of HCN. The spectra were obtained by means of the vibrationally mediated photodissociation technique. Analysis of the spectra revealed four bands with Sigma-Sigma structures that, once fitted, provided the energies and rotational constants of four new, high...

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