How important is the state-specific solvation desscription for absorption/emission spectra simulation

MANUEL K. STRAUSS; SAJRA BURNIC; ANDREAS THEILER; ROMINA BRASCA; MARIA J. CULZONI; ANNE-MARIE KELTERER

Banská Bystrica

Simposio; XIV Central Symposium on Theoretical Chemistry (CESTC); 2015

The quantum chemical description of molecules includes thecomputation of their structure and properties, as well as theinteraction with their surrounding. The special interest of theComputational Chemistry group at the Institute of Physicaland Theoretical Chemistry is the theoretical investigation ofthe photophysics of organic fluorophores and photoacids withinclusion of the solvent effect. Computational spectroscopypredicts absorption and emission spectra and helps to explainthe excitation and emission processes.Density Functional Theory (DFT) is applied for all calculationsby using M06-2X/aug-cc-pVDZ and the program Gaussian09.The photophysics and the proton transfer of 2-Naphtol, 3-Hydroxypyridine and Salicylic Acid are investigated in waterwith and without the inclusion of explicit solvent molecules.These three benchmark molecules are photoacids possessinga higher propensity to donate their proton in the excited staterather than in the ground state. This poster presents theseaspects by comparing gas phase calculations with twosolvation models which differ in their description of excitationand relaxation.The absorption and emission spectra of the three benchmarkmolecules are modelled on the basis of the computed verticalexcitations and emissions, respectively, with a consecutiveconvolution of spectra with Gaussian broadened transitionlines. The vertical transition data (transition energy, oscillatorstrength, Stokes shift) are compared for the gas phase andsolvation model calculations with available experimentalliterature data.