title: Effective method to compute vibrationally resolved optical spectra of large molecules at finite temperature in the gas phase and in solution.
abstract: The authors present a new method for the computation of vibrationally resolved optical spectra of large molecules, including the Duschinsky rotation of the normal modes and the effect of thermal excitation. The method automatically selects the relevant vibronic contributions to the spectrum, independently of their frequency, and it is able to provide fully converged spectra with moderate computational times, both in vacuo and in solution. By describing the electronic states in the frame of the density functional theory and its time-dependent extension, they computed the room temperature absorption spectra of coumarin C153 and trans-stilbene in cyclohexane and the phosphorescence spectrum of porphyrazine in gas phase, showing that the method is fast and efficient. The comparison with experiment for trans-stilbene and coumarin C153 is very satisfactory, confirming the progress made toward a reliable method for the computation and interpretation for the optical spectra of large molecules.
authors.affiliation: Istituto per i Processi Chimico-Fisici-CNR, Area della Ricerca del CNR Via Moruzzi 1, I-56124 Pisa, Italy. f.santoro@ipcf.cnr.it
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Santoro
authors.forename: Alessandro
authors.initials: A
authors.lastname: Lami
authors.forename: Roberto
authors.initials: R
authors.lastname: Improta
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Barone
mesh_terms: D003198:Computer Simulation; D003374:Coumarins / Q000737:chemistry*; D005740:Gases / Q000737:chemistry*; D006576:Heterocyclic Compounds, 4 or More Rings / Q000737:chemistry*; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D044367:Phase Transition; D012996:Solutions; D013057:Spectrum Analysis / Q000379:methods*; D013267:Stilbenes / Q000737:chemistry*; D013696:Temperature; D014732:Vibration
chemical_list: D003374:Coumarins; D005740:Gases; D006576:Heterocyclic Compounds, 4 or More Rings; D012996:Solutions; D013267:Stilbenes; C517738:coumarin C153