Avviso di Conferenza: Alberto Baiardi - "A versatile computational platform for the simulation and interpretation of vibronic spectra" - Edificio C11, Sala del Consiglio (1° piano)

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Data evento
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22/10/2015 - 15:00
Data fine evento: 
22/10/2015 - 16:00
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16/10/2015

AVVISO DI CONFERENZA

Giovedì 22 Ottobre 2015, ore 15:00, Sala del Consiglio  (I piano)

 

Dott. Alberto Baiardi

(Scuola Normale Superiore, Pisa)

 

A versatile computational platform for the simulation and
interpretation of vibronic spectra
 
 

Electronic spectroscopy is nowadays among the most powerful tools for the study of chemical systems. However, proper assignment of spectra relies more and more on quantum mechanical (QM) computations, for both interpretative and predictive aspects. The way in which electronic spectra are simulated is often basic, with a single peak per electronic transition, and broadening effects are simulated using a symmetric distribution function. This approach neglects completely the vibro-electronic (vibronic) effects, and therefore cannot be used for the interpretation of high resolution data showing a detailed vibrational structure, as well as for low-resolution spectra, whose asymmetric peaks cannot be reproduced by a single distribution function.
In order to overcome those limitations, a computational platform for the simulation of vibronic spectra has been implemented. Two parallel theories have been implemented: in the so-called sumover-states or time-independent (TI) method, the spectrum is obtained as the sum of all the transitions between the vibrational initial and final states treated independently from one another. Within the alternative time-dependent (TD) approach, based on Feynmann path integral formalism, fully converged spectra can be obtained with the inclusion of temperature effects without additional computational cost. Both the frameworks have been applied to the simulation of different types of spectroscopies, like one-photon absorption (OPA) and emission (OPE), as well as to electronic circular dichroism (ECD) and circularly polarized luminescence (CPL). The further extension of the tool to vibrational resonance Raman spectroscopy (rR) will be discussed. In order to describe the reliability of the tool, the approximations underlying the theoretical framework will be presented, together with their respective strengths and limitations. Finally, the recent extension of the previous framework to support internal coordinates, which improves the description of large and flexible systems, will be described.
In order to show the reliability of the implementation of this theory, several applications to the simulation of vibronic spectra will be presented, taking molecular systems of biological and technological interest as test-cases.

 References:

Barone V., Bloino J., Biczysko M., Santoro F., Journal of the Chemical Theory and Computation, 2009, 5, 540
Baiardi A., Bloino J., Barone V., Journal of the Chemical Theory and Computation, 2013, 9, 4097
Baiardi A., Barone V., Bloino J., Chirality, 2014, 26, 588
Baiardi A., Bloino J., Barone V., The Journal of Chemical Physics, 2014, 141, 114108
Baiardi A., Bloino J., Barone V., The Journal of the Chemical Theory and Computation, 2015, 11, 3267.

 

Ultimo aggiornamento: 16-10-2015 - 12:49
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