A combined experimental and theoretical analysis on molecular structure and vibrational spectra of 2,4-dihydroxybenzoic acid.

The FT-IR and FT-Raman spectra of 2,4-dihydroxybenzoic acid (2,4-DHBA) in the solid phase have been recorded in the regions 4000-400 cm(-1) and 3700-100 cm(-1), respectively. The total energies of sixteen stable conformers for 2,4-DHBA have been calculated by density functional theory (DFT) using the B3LYP method with 6-311++G (d, p) basis set, and the C1 conformer with the lowest energy was obtained, the geometrical parameters between X-ray experiment diffraction and DFT calculation show good consistency. Furthermore, the vibrational frequencies of 2,4-DHBA were computed, and the detailed analysis of vibrational spectra was made on the basis of the potential energy distribution (PED) by combining experimental with theoretical data.

Experimental and theoretical studies on the vibrational spectra of trans-3-phenylacryloyl chloride.

The infrared and Raman spectra of trans-3-phenylacryloyl chloride (TPC) were reported and compared with the theoretical results calculating at B3LYP/6-311++G (d, p) level. Both wavenumbers and intensities obtained from the experimental and theoretical spectra were in good agreement. A complete spectral assignment was made with the aid of potential energy distribution (PED) based on the scaled quantum mechanical (SQM) force field method.

Micro-Raman analysis of the pigments on painted pottery figurines from two tombs of the Northern Wei Dynasty in Luoyang.

The pigments on the painted pottery figurines from two tombs of Northern Wei Dynasty (AD 386-534) in Luoyang were analyzed by Raman microscopy. All the pigments were identified compared with the Raman spectra of standard pigments. The red pigments were identified as haematite, the blue pigment as lapis lazuli, the green pigment as malachite, the black pigment as carbon black and the white pigment as calcite.

[Raman, FTIR spectra and normal mode analysis of acetanilide].

The Raman and FTIR spectra of acetanilide (ACN) were measured experimentally in the regions of 3 500-50 and 3 500-600 cm(-1) respectively. The equilibrium geometry and vibration frequencies of ACN were calculated based on density functional theory (DFT) method (B3LYP/6-311G(d, p)). The results showed that the theoretical calculation of molecular structure parameters are in good agreement with previous report and better than the ones calculated based on 6-31G(d), and the calculated frequencies agree well with the experimental ones.

[Study on the configuration and applications of high spectral resolution Raman spectrometer].

In the present paper the authors studied theoretically and experimentally the relationship between spectral resolution and grating density, the limitations to improve the spectral resolution by using high density grating, the use of longer focal length grating to increase spectral resolution without compromising instrument throughput and the effect of slit width on spectral resolution and sensitivity. Finally, two experiment results were provided to show why higher spectral resolution is important to ensure that critical information is not lost during a Raman measurement. Stressed silicon was produced by growing a thin crystalline layer of Si on an Si(x)Ge(1-x) substrate.