Tuesday, 9 October 2012

Terahertz and mid-infrared spectroscopy of benzene-1,2-diol

Journal of Molecular Spectroscopy

Available online 2 October 2012

ZP Zheng, WH Fan, H Yan, J Liu, WZ Yang, SL Zhu 

State Key Laboratory of Transient Optics and Photonics, Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi’an 710119, China


The terahertz (8-128 cm-1) and mid-infrared spectra (400-2000 cm-1) of benzene-1,2-diol at room temperature were measured by using terahertz time-domain spectroscopy and Fourier transform infrared spectroscopy, respectively. Comparing the experimental terahertz and mid-infrared spectra with computed results by density functional theory, we find that all the terahertz spectral features come from inter-molecular vibrations, and the mid-infrared spectral features mainly originate from intra-molecular vibrations, although inter-molecular vibrations still make the contributions in some extent.
The terahertz (THz) and mid-infrared (MIR) spectra of benzene-1,2-diol in the solid state have been modeled by density functional theory (DFT). Calculations of the vibrational spectra based on the optimized geometries provided a good fit to the observed spectra, and a more reasonable spectral reproduction has been achieved than those in previous work. For THz spectrum, the simulation based on the varied unit cell dimension has clearly shown that THz spectral reproduction is affected by the temperature change of unit cell. For MIR spectrum, band assignments are reported in terms of potential-energy distribution (PED), which differ to those previously reported for benzene-1,2-diol in some respects.

Full-size image (27 K)

... Experimentally, THz spectrum (8-128 cm -1 ) of benzene-1,2-diol was measured by using TPS
spectra 3000 (TeraView Limited) with the spectral resolution of 1.2 cm -1 . MIR spectrum....

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