Ongoing work has been dedicated in our group to develop a multi-frequency virtual spectrometer able to compute a wide range of properties and spectra for molecules of biological and technological interest with account for environmental effects[1]. Recently, two extensions have been included in this platform to compute vibrationally-averaged properties[2], vibrationally-resolved electronic spectra[3,4] and anharmonic vibrational spectra[2]. Both have been designed to be robust and versatile, and usable as black-box procedures. They are based on general formulations and are highly modular to facilitate the addition of new spectroscopies or the inclusion of faster algorithms to improve the efficiency of the program.This presentation will give an overview of some of the features of these modules by illustrating with some case studies their design and capabilities. For instance, vibrationally resolved electronic spectra (absorption, emission, electronic circular dichroism) can be computed using both quantum mechanical time-dependent and time-independent formulations, and different approximations for transition dipole moment expressions and potential energy surface models are available. Regarding anharmonic vibrational spectra, they are computed using second-order perturbation theory. In particular, a consistent method is used to overcome the well-known problem of Fermi resonances in vibrational energy calculations[5]. The anharmonic correction is also applied to intensity calculations, allowing us to compute infrared, vibrational circular dichroism and Raman spectra.[1] V. Barone, A. Baiardi, M. Biczysko, J. Bloino, C. Cappelli, F. Lipparini, Phys. Chem. Chem. Phys. 2012 14, 12404[2] J. Bloino, V. Barone, J. Chem. Phys. 2012, 136, 124108[3] V. Barone, J. Bloino, M. Biczysko, F. Santoro, J. Chem. Theory Comput. 2009, 5, 540[4] J. Bloino, M. Biczysko, F. Santoro, V. Barone, J. Chem. Theory Comput. 2010, 6, 1256[5] J. Bloino, M. Biczysko, V. Barone, J. Chem. Theory Comput. 2012, 8, 1015

Design of a multifrequency virtual spectrometer: Accurate simulation of vibrational and electronic spectra

248th National Meeting (2014)

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