Electron diffraction and quantum chemical study of the structure and internal rotation in nitroethane

Diffraction Measurements and Equilibrium Parameters

“…In such a situation, parameters for treatment of diffraction data are sometimes determined by calculating the "minimum energy path," that is, quantum-mechanical calculations are performed with the optimization of the geometries that arise in scanning the system along, for instance, the torsional coordinate [20]. It may well be (almost inevitable) that the "torsional vibration" along the minimum energy path will then include coordinates inconsistent with it by symmetry.…”

An alternative gas-phase electron diffraction and quantum chemical study of nitroethane

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a b s t r a c tThe results of alternative gas-phase electron diffraction (GED) study of nitroethane are compared with those reported in the previous study by Tarasov et al [1]. A fairly large reliability factor (R = 6.1%) obtained in that work, even though the intensity data over the range s > 27 Å À1 were excluded from the analysis, was one of the reasons for undertaking this investigation.

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“…Recently, a gas-phase electron diffraction (GED) study of nitroethane was performed by Tarasov et al [1] based on a certain theoretical model for large-amplitude motions. However, the approximation of internal rotation of nitroethane used in [1] has some deficiencies.…”

“…However, the approximation of internal rotation of nitroethane used in [1] has some deficiencies. Quantum chemical calculations predicted different most stable conformations for nitroethane including the planar and orthogonal forms (Fig.…”

“…The QCISD/ccpVT(D)Z method predicts a minimum for the planar structure ( Fig. 6 in [1]), while the MP2/cc-pVT(D)Z calculations lead to a minimum for the orthogonal form ( Fig. 5 in [1]).…”