Theoretical study of the C–H/O–H stretching vibrations in malonaldehyde
| Autor: | G. A. Pitsevich, A. E. Malevich, I. Yu. Doroshenko, V. Pogorelov, E.N. Kozlovskaya, Valdas Sablinskas, Vytautas Balevicius |
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| Rok vydání: | 2015 |
| Předmět: |
Spectrophotometry
Infrared Proton Hydroxyl Radical Chemistry Anharmonicity Molecular Conformation Hydrogen Bonding Context (language use) Hydrogen atom Models Theoretical Vibration Potential energy Atomic and Molecular Physics and Optics Analytical Chemistry symbols.namesake Malondialdehyde Excited state symbols Thermodynamics Physics::Chemical Physics Atomic physics Perturbation theory Raman spectroscopy Instrumentation Spectroscopy |
| Zdroj: | Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy. 145:384-393 |
| ISSN: | 1386-1425 |
| DOI: | 10.1016/j.saa.2015.02.067 |
| Popis: | IR and Raman spectra of the malonaldehyde molecule and its deuterated analogues were calculated in the B3LYP/cc-pVQZ approximation. Anharmonicity effects were taken into account both in the context of a standard model of the second order perturbation theory and by constructing the potential energy surfaces (PES) with a limited number of dimensions using the Cartesian coordinates of the hydroxyl hydrogen atom and the stretching coordinates of С–Н, C–D, O–H, and O–D bonds. It was shown that in each of the two equivalent forms of the molecule, besides the global minimum, an additional local minimum at the PES is formed with the energy more than 3000 cm −1 higher than the energy in the global minimum. Calculations carried out by constructing the 2D and 3D PESs indicate a high anharmonicity level and multiple manifestations of the stretching О–Н vibrations, despite the fact that the model used does not take into account the splitting of the ground-state and excited vibrational energy levels. In particular, the vibration with the frequency 3258 cm −1 may be associated with proton transfer to the region of a local minimum of energy. Comparing the results obtained with the experimental data presented in the literature allowed us to propose a new variant of bands assignments in IR and Raman spectra of the molecule in the spectral region 2500–3500 cm −1 . |
| Databáze: | OpenAIRE |
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