Calculating vibrational spectra using modified Shepard interpolated potential energy surfaces

2008 ◽  
Vol 129 (2) ◽  
pp. 024104 ◽  
Author(s):  
Christian R. Evenhuis ◽  
Uwe Manthe
Keyword(s):  
Potential Energy ◽  
Vibrational Spectra ◽  
Potential Energy Surfaces ◽  
Energy Surfaces

Bond-length alternation and vibrational spectra of polyacetylene

1984 ◽  
Vol 62 (12) ◽  
pp. 1226-1231 ◽  
Author(s):  
M. Takahashi ◽  
J. Paldus
Keyword(s):  
Potential Energy ◽  
Bond Length ◽  
Vibrational Spectra ◽  
Potential Energy Surfaces ◽  
Reasonable Agreement ◽  
Energy Surface ◽  
Equilibrium Geometry ◽  
Bond Length Alternation ◽  
Cyclic Polyene ◽  
Energy Surfaces

The effect of bond-length alternation on the main features of the Raman vibrational spectra of polyacetylene is examined. It is shown that the semiempirical potential energy surfaces for cyclic polyene models, which display the bond-length alternating equilibrium geometry, yield vibrational frequencies that are in reasonable agreement with observed principal Raman bands. However, these frequencies are rather insensitive to the details of the potential energy surface employed, thus explaining the controversy between earlier computations (Ovchinnikov et al.) and the experimental evidence of bond-length alternation in all-trans polyacetylene (Fincher, Jr., et al.). Nevertheless, the normal mode character of these vibrations qualitatively changes with the introduction of the bond-length alternation.

Synthesis, Characterization and TheoreticalStudies of Nand#39;-(4-methoxybenzylidene)benzenesulfonohydrazide

2021 ◽  
Vol 43 (2) ◽  
pp. 212-212
Author(s):  
H G zin Aslan and L tfiye Aydin H G zin Aslan and L tfiye Aydin
Keyword(s):  
Potential Energy ◽  
Gas Phase ◽  
Vibrational Spectra ◽  
Potential Energy Surfaces ◽  
Solid Phase ◽  
Nbo Analysis ◽  
Basis Set ◽  
Basis Sets ◽  
Stable Conformer ◽  
Energy Surfaces

Nand#39;-(4-methoxybenzylidene)benzenesulfonohydrazide was synthesized and elemental analysis was conducted; IR, Raman, 1H, and 13C NMR spectral data were recorded. The potential energy surfaces (PES) of the Nand#39;-(4-methoxybenzylidene)benzenesulfonohydrazide molecule were obtained by selected degree of torsional freedom, which varied from 0o to 360and#186; in 4and#186; increments. The conformers were optimized by using a (DFT/B3LYP/6-31G(d,p)) basis set in the gas phase. The eleven conformers in the gas phase of the obtained molecule were determined and the most stable conformer (conformer 1) was re-optimized by three different basis sets of 6-31G(d,p), 6-311G(d,p), and LanL2Dz. HOMO-LUMO analyses were performed. NBO analysis was performed to describe the around of intramolecular charge transfer. The vibrational spectra were measured in solid phase IR and detailed analysis of the vibrational spectra of conformer 1 was done; all the bands of the spectra were interpreted by the use of the potential energy distributions (PED) and the molecular electrostatic potential (MEP) was plotted.

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