Showing papers on "Infrared spectroscopy correlation table published in 2013"

Fourier Transform Infrared Spectroscopy

Abstract: Fourier transform infrared (FTIR) spectroscopy is a rapid, economical, easy, and non-destructive technique. The IR spectrum of a clay mineral is sensitive to its chemical composition, isomorphous substitution, layer stacking order, or structural modifications. This makes FTIR spectroscopy the most informative single technique not only for clay mineral composition and structure but also for interactions of the clay minerals with inorganic or organic compounds. After a brief presentation of the principles of the technique, the chapter gives an overview of the potential of FTIR for mineralogical identification of clay minerals samples, and for studying reactions with water and organic molecules. This chapter includes data from all three infrared regions, that is, far, middle, and near.

Femtosecond Two-Dimensional Infrared Spectroscopy of N-Ethypropionamide

Abstract: Femtosecond two-dimensional infrared (2D IR) spectroscopy, steady-state infrared spectroscopy, and computational methods are used to examine the ultrafast structural dynamics of a β-peptide model compound, N-ethylpropionamide (NEPA). NEPA has amide-I vibrational characteristics similar to that in an α-peptide, which shows sensitivity to molecular structure and chemical environment. The 2D IR spectral dynamics reveal a spectral diffusion time of ~1 ps, which is believed to be consistent with the time scale of the structural dynamics of the amide-water hydrogen bond.

Studied on Simulation Spectra of Protein Secondary Structures by Two-Dimensional Infrared Correlation Spectroscopy

Abstract: The function of Voigt was used to simulate the infrared absorption spectra of protein secondary structures and amide I band,the band at 1680cm-1 was highly overlapped.In order to study the resolving power of two-dimensional infrared correlation spectroscopy in highly overlapped band,the 1680cm-1 was selected as studied aim.When only the amplitude of peak at 1680cm-1 was variety,its synchronous two-dimensional infrared correlation spectrum could presented accurately.When the amplitude of the band pair at 1680and 1640cm-1 had variety,the synchronous two-dimensional infrared correlation spectrum not only represented wave number accurately,but also got the information that the sensitivity of band at 1680cm-1is more than the band at 1640cm-1 by external perturbation.The synchronous cross-peak was negative at 1680cm-1 and 1640cm-1.It showed the intensity change of the band pair occurs in the opposite direction.At asynchronous cross-peak was negative at(1680cm-1,1640cm-1),it showed the intensity decrease at 1640cm-1 occurs before the intensity increase at 1680cm-1.The simulation result showed that the two-dimensional infrared correlation spectroscopy had advantage of highly resol- ving power and sensitivity.It could be used to study highly overlapped amide I,and get more information of protein secondary structures.

Accurate ro-vibrational rest frequencies of DC4H at infrared and millimetre wavelengths

Abstract: Context. Diacetylene, C4H2, has been identified in several astronomical environments through its infrared spectrum. In contrast, monodeuterated diacetylene (DC4H) has not been detected in space so far owing to the low isotopic abundance of deuterated species but also to the rather poor laboratory spectroscopic characterisation of this molecule. Aims. The aim of this work is to provide accurate spectroscopic parameters for DC4H to achieve reliable predictions for both its spectra at millimetre and infrared wavelengths. Methods. We studied the rotational spectrum of DC4H in the range 85–615 GHz by millimetre-wave spectroscopy and the infrared spectrum below 1000 cm −1 by high-resolution, Fourier-transform spectroscopy. Several pure rotational transitions were recorded in the ground state and in excited vibrational bending states. The three fundamental bands v6, v7 ,a ndv8 have been identified and assigned in the infrared spectrum. Results. The rotational transitions were analysed together with the infrared data in a global fit that produces very accurate rovibrational parameters. The observed frequencies and wavenumbers are reported to provide precise guidance for astronomical searches.

Femtosecond Two-Dimensional Infrared Spectroscopy of N-Ethypropionamide

Abstract: Femtosecond two-dimensional infrared(2D IR) spectroscopy,steady-state infrared spectroscopy,and computational methods are used to examine the ultrafast structural dynamics of a β-peptide model compound,N-ethylpropionamide(NEPA).NEPA has amide-I vibrational characteristics similar to that in an α-peptide,which shows sensitivity to molecular structure and chemical environment.The 2D IR spectral dynamics reveal a spectral diffusion time of ～1 ps,which is believed to be consistent with the time scale of the structural dynamics of the amide-water hydrogen bond.