Related Experiment Video
Updated: May 18, 2026

Raman and IR Spectroelectrochemical Methods as Tools to Analyze Conjugated Organic Compounds
Published on: October 12, 2018
Comment on: "FT-IR, FT-Raman and UV spectral investigation; computed frequency estimation analysis and electronic
Andrea Alparone1, Vito Librando
1Research Centre for Analysis, Monitoring and Minimization Methods of Environmental Risk, viale A. Doria 6, Catania 95125, Italy.
Abstract:
The title paper [1] incorrectly establishes that, in gas phase the global minimum energy structure of 1-nitronaphthalene is planar (C(s) symmetry). By contrast, present calculations indicate that the planar C(s) form is an unstable structure on the potential energy surface, exhibiting an imaginary vibrational wavenumber value corresponding to the torsional mode of the nitro group around the C-N bond. At the B3LYP/6-311++G(d,p) level of calculation the global minimum energy structure of 1-nitronaphthalene in gas phase has a non-planar geometry, characterized by O-N-C-C dihedral angles of ca. 30° and lying 0.35 kcal/mol below the C(s) form.
Related Concept Videos
Raman Spectroscopy: Overview
However, a small fraction of the scattered light exhibits a frequency shift due to the exchange of energy between the incident photons and the...
IR Frequency Region: Fingerprint Region
The...
Raman Spectroscopy Instrumentation: Overview
The monochromatic laser source, typically using visible or near-infrared radiation, generates a highly focused beam of light. This light interacts with the molecules of the sample, scattering some of the light. Liquid and gaseous samples are usually tested in ordinary glass capillaries, while solids can be analyzed as powders packed in capillaries or as potassium...
UV–Vis Spectroscopy: Molecular Electronic Transitions
UV–Vis Spectroscopy of Conjugated Systems
One of the factors influencing λmax is the extent of conjugation in the...
IR Absorption Frequency: Delocalization
In IR spectroscopy,...

