Terahertz spectroscopy of dicyanobenzenes: Anomalous absorption intensities and spectral calculations

Esentürk, Okan
Heilweil, E. J.
Terahertz absorption spectra of three isomeric structures of dicyanobenzene in chloroform solution and solid phase at 298 K are reported. These spectra exhibit enhanced absorption in low THz range compared to most organic systems because of strong coupling to phonon modes. Molecular vibrational spectral calculations show strong correlation with the experiment especially for solution spectra. All intramolecular modes were assigned and intermolecular modes identified. Out-of-plane intramolecular modes at low frequency exhibit similar to 75 cm(-1) blue shifts as the secondary CN group moves from the para to ortho position on the benzene ring, whereas almost no frequency shift occurs for low-frequency in-plane modes.


Dielectric Properties of Ethanol and Gasoline Mixtures by Terahertz Spectroscopy and an Effective Method for Determination of Ethanol Content of Gasoline
ARIK, Enis; Altan, Hakan; Esentürk, Okan (American Chemical Society (ACS), 2014-05-01)
Investigation of frequency dependent permittivity of mixture solutions provides information on the role of intermolecular interactions on relaxation processes of solvent and solute molecules. In this study the dielectric properties of ethanol/gasoline mixtures in the terahertz spectral region are investigated. Frequency dependent absorption coefficients, refractive indices, and complex permittivities of pure ethanol and gasoline, and their mixtures at varying ethanol volume percentages (v/v %) are reported....
Valence-shell electron energy-loss spectra of formic acid and acetic acid
Ari, T; Guven, MH (2000-01-01)
Gas phase optical absorption spectra of formic acid and acetic acid in the energy ranges 5.0-11.3 and 4.4-11.3 eV, respectively, have been previously recorded. It is generally agreed that of the four successive bands observed in the spectra of these compounds, the first corresponds to n --> pi* transition. However, various assignments have been proposed for the following three bands. In the present study, electron energy-loss spectra of formic acid and acetic acid vapours at 70 eV impact energy and 0 degree...
Pyrolysis Studies to Investigate Effects of Polymerization Techniques on Structure and Thermal Behavior of Poly(1,2-Epoxy-4-Epoxyethylcyclohexanes)
Hacaloğlu, Jale; Önal, Ahmet Muhtar (1995-01-01)
Thermal behaviors of poly(1,2-epoxy-4-epoxyethylcyclohexanes) (poly-EECH), polymerized by electroinitiation, radiation, and catalytic action of HClO4 and BF3-etharate, have been studied by direct pyrolysis MS and evolved gas analyses by mass and FT-IR spectrometric techniques. Direct pyrolysis experiments indicated that electroinitiated and catalytic polymerization of EECH with the use of BF3-etharate produced the least stable polymers thermally. High mass peaks were related to the presence of blocks propag...
Chain-extended bismaleimides .1. Preparation and characterization of maleimide-terminated resins
Yerlikaya, Z; Oktem, Z; Bayramlı, Erdal (1996-01-03)
Starting from aromatic diamines, a series of bismaleimides (BMIs) and maleimide-terminated structural resins were prepared in solution and characterized. Maleimide-terminated resins were prepared through Michael addition reaction with 3/2 molar ratio of bismaleimide and aromatic diamine as reactants. The structural analysis was performed by FTIR and H-1-NMR spectroscopy. Thermal properties are investigated by TGA, DTA, and DSC. Number-average molecular-weights of the resins were determined by cryoscopy. The...
Nanoceria-Supported Ruthenium(0) Nanoparticles: Highly Active and Stable Catalysts for Hydrogen Evolution from Water
Demir Arabacı, Elif; Önal, Ahmet Muhtar (American Chemical Society (ACS), 2018-02-21)
Ruthenium(0) nanoparticles supported on nanoceria (Ru-0/CeO2) were prepared by reduction of Ru3+ ions on the surface of ceria using aqueous solution of NaBH4. The Ru-0/CeO2 samples were characterized by advanced analytical tools and employed as electrocatalysts on the glassy carbon electrode (GCE) in hydrogen evolution from water. The GCE, modified by Ru-0/CeO2 (1.86 wt % Ru), provides an incredible electrocatalytic activity with a high exchange current density of 0.67 mA.cm(-2), low overpotential of 47 mV ...
Citation Formats
O. Esentürk and E. J. Heilweil, “Terahertz spectroscopy of dicyanobenzenes: Anomalous absorption intensities and spectral calculations,” CHEMICAL PHYSICS LETTERS, pp. 71–77, 2007, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/45852.