Many-body, Dynamic and Environmental Effects on Spectroscopic Properties: Toward a Multifrequency Virtual Spectrometer.

Vincenzo Barone

Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa, Italy

The increased necessity to design new responsive materials with unique properties, which could be tuned and controlled by means of appropriate external sources, for specific applications in different sectors such as aerospace, electronics, ceramics, packaging, drug delivering and targeting, requires a cooperative experimental/computational effort. Interpretation and prediction of the spectroscopic properties of these composite systems have been obtained through calibrated computational protocols defined in our group. In the framework of the ERC Advanced Grant Project DREAMS “Development of a Research Environment for Advanced Modeling of Soft Matter”, GA N° 320951 we are extending our new multifrequency virtual spectrometer [1] toward larger systems including nanoparticles and polymers. In this way, molecular motions and supra-molecular interactions in real-size structures can be captured combining all levels of theory, ranging from classical molecular dynamics simulations (CMDs) to full quantum mechanics calculations (QMc). The combination of CMDs, based on accurately parameterized force fields, and QMc, based on density functional theory (DFT) and its time-dependent extension (TD-DFT) have been used to simulate both the absorption and emission spectra of dyes in solution [2] and interacting with different kinds of  nanoparticles [3], and succeeded in elucidating the mechanisms which determined the modifications of different spectroscopic properties (IR, Raman, UV-vis, etc.) observed experimentally. The photophysical properties of organic chromophores incorporated (grafte/dispersed) in apolar polymer matrices have also been studied in detail [4] and the influence of the polymer bundle on the dynamics and conformational properties of the dopants together with the configurations responsible for both the absorption and emission spectra have been identified.

[1] V. Barone, A. Baiardi, M. Biczisko, J. Bloino, C. Cappelli, F. Lipparini, Implementation and validation of a multi-purpose virtual spectrometer for large systems in complex environments, PHYSICAL CHEMISTRY CHEMICAL PHYSICS 14, 12404-12422 (2012).

[2] F. Lipparini, F. Egidi, C. Cappelli, V. Barone, The Optical Rotation of Methyloxirane in Aqueous Solution: A Never Ending Story?, JOURNAL OF CHEMICAL THEORY AND COMPUTATION 9, 1880-1884 (2013).

[3] A. Pedone, J. Bloino, V. Barone, Role of host-guest interactions in tuning the optical properties of coumarin derivatives incorporated in MCM-41: a TD-DFT investigation, JOURNAL OF PHYSICAL CHEMISTRY C 116, 17807-17818 (2012).

[4] G. Prampolini, F. Bellina, M. Biczysko, C. Cappelli, L. Carta, M. Lessi, A. Pucci, G. Ruggeri, V. Barone, Computational design, synthesis, and mechanocromic properties of new thiophene-based pi-conjugated chromophores, CHEMISTRY 19, 1996-2004 (2013).