The interpretation of molecular vibrational spectroscopic signals in terms of atomic motion is essential to understand molecular mechanisms and for chemical characterization. The signals are usually assigned after harmonic normal mode analysis, even if molecular vibrations are known to be anharmonic. Here we obtain the quantum anharmonic vibrational eigenfunctions of the 11-atom protonated glycine molecule and we calculate the density distribution of its nuclei and its geometry parameters, for both the ground and the O-H stretch excited states, using our semiclassical method based on ab initio molecular dynamics trajectories. Our quantum mechanical results describe a molecule elongated and more flexible with respect to what previously thought. More importantly, our method is able to assign each spectral peak in vibrational spectroscopy by showing quantitatively how normal modes involving different functional groups cooperate to originate that spectroscopic signal. The method will possibly allow for a better rationalization of experimental spectroscopy.
Anharmonic quantum nuclear densities from full dimensional vibrational eigenfunctions with application to protonated glycine / C. Aieta, M. Micciarelli, G. Bertaina, M. Ceotto. - In: NATURE COMMUNICATIONS. - ISSN 2041-1723. - 11:1(2020 Aug 28).
|Titolo:||Anharmonic quantum nuclear densities from full dimensional vibrational eigenfunctions with application to protonated glycine|
AIETA, CHIARA DONATELLA (Primo)
MICCIARELLI, MARCO (Secondo)
BERTAINA, GIANLUCA (Penultimo)
CEOTTO, MICHELE (Ultimo) (Corresponding)
|Parole Chiave:||Glycine; Molecular Structure; Quantum Theory; Spectrophotometry, Infrared; Thermodynamics; Molecular Dynamics Simulation; Vibration|
|Settore Scientifico Disciplinare:||Settore CHIM/02 - Chimica Fisica|
|Progetto:||Divide and Conquer ad initio semiclassical molecular dynamics for spectropic calculations of complex systems (SEMICOMPLEX)|
|Data di pubblicazione:||28-ago-2020|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1038/s41467-020-18211-3|
|Appare nelle tipologie:||01 - Articolo su periodico|