Presentation on theme: "Influence of solvation on 1-aminonaphthalene photophysics: ultrafast relaxation in the isolated molecule, molecular clusters and solution by Raúl Montero,"— Presentation transcript:
Influence of solvation on 1-aminonaphthalene photophysics: ultrafast relaxation in the isolated molecule, molecular clusters and solution by Raúl Montero, Alvaro Peralta Conde, Fernando Castaño and Asier Longarte Departamento de Química Física Universidad del País Vasco (UPV/EHU) 65th Ohio Spectroscopy Meeting
Motivation To understand the photophysics of 1-aminonaphthalene (AMN), in particular the dynamics of the L a /L b state coupling. Influence of solvation on the photophysics of the molecule. The interaction of polar solvents with the amino group. AMN(H 2 O) 1-3 clusters From H-bonded clusters to bulk. AMN in methanol solutions.
65th Ohio Spectroscopy Meeting AMN Electronic Spectroscopy Theoretical Calculations:CASSCF/CASPT2 * M. Merchán and L. Serrano-Andrés. University of Valencia Fluorescence Spectroscopy LIF Excitation Spectrum Dispersed Emission * S. Jiang and D. H. Levy. J. Phys. Chem. A, 106 (2002) 8590-8598.
65th Ohio Spectroscopy Meeting AMN Short Time Dynamics
65th Ohio Spectroscopy Meeting AMN Long Time Dynamics Excitation (nm)τ 2 (ps) Probe 800 nm 311940±138 308710±100 304513±70 298348±30 294290±35 286120±10 28084±6 26735±5 24516±2 23514±2 A lifetime τ 2 is found at longer time scales, which shortens from 1 ns to 14 picoseconds with the excitation energy. This component is attributed internal conversion to the ground state and intersystem crossing.
65th Ohio Spectroscopy Meeting AMN in Methanol Solutions Fluorescence Spectra Water Cyclohexane Absorption Emission
Time (fs) Time (ps) Time Resolved Fluorescence AMN in Methanol Solutions 65th Ohio Spectroscopy Meeting τ 1 =500 fs τ 2 =11 ps
65th Ohio Spectroscopy Meeting Effect of Solvation on AMN Photophysics S0S0 τ 1 =500 fs LbLb LaLa Solute Coordinate L b →L a Internal Conversion S0S0 Solvent Coordinate τ 2 =11 ps LbLb LaLa Dynamic Stokes Shift
65th Ohio Spectroscopy Meeting Dynamic Stokes Shift * J. L. Perez Lustres, et al. Angew. Chem. Int. Ed. 2005, 44, 5635 –5639.
65th Ohio Spectroscopy Meeting Remarks On the way… AMN solvated by two or three water molecules reproduces the behavior found in solution. The observed photophysics can be explained in terms of the different time-scale response of the solute and solvent coordinates. The reorganization of the solvent molecules can explained the anomalous electronic spectroscopy of the amino-water complexes. Ab initio calculations of the L a /L b potential energy surfaces of the AMN-Water clusters. Time resolved measurements on deuterated methanol and solvents with similar polarity. …probing the dynamical shift response directly on the solvent coordinates.
65th Ohio Spectroscopy Meeting Acknowledgments Grupo de Química Teórica (UV) Prof. Luis Serrano-Andrés Prof. Manuela Merchán Israel González-Ramírez Angelo Giussani Raúl Montero Dr. Álvaro Peralta Conde Prof. Fernando Castaño Grupo de Espectroscopía (UPV/EHU) Financial Support Spanish Ministry of Science and Innovation CONSOLIDER Program Basque Goverment UPV/EHU