Ultrafast Excited-state Proton Transfer Processes: Energy Surfaces and On-the-fly Dynamics SimulationsReport as inadecuate




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Croatica Chemica Acta, Vol.82 No.1 June 2009. -

The excited-state intramolecular proton transfer ESIPT is reviewed for several benchmark systems o-hydroxybenzaldehyde OHBA, salicylic acid and 2-2′-hydroxyphenyl-benzothiazole HBT in order to verify the applicability of the time-dependent density functional theory TDDFT and the resolution-of-the-identity approximate second-order coupled cluster RI-CC2 methods. It was found that these approaches are very well suited for the description of ESIPT processes. A comparative investigation of previous and new excited-state dynamics simulations is performed for HBT, 10-hydroxybenzohquinoline HBQ, and 2,2′-bipyridyl-3,3′-diol BPOH2. The time scale for the ESIPT process in these systems ranges in the time interval of 30−40 fs for HBT and HBQ and amounts to about 10 fs for the first proton transfer step in BPOH2. The dynamics simulations also show that the proton transfer in HBT is strongly supported by skeletal modes and the proton plays a rather passive role, whereas in HBQ a semipassive mechanism is found due to its increased rigidity in comparison to HBT. The special role of the double proton transfer in BPOH2 is discussed as well.

density functional theory; on-the-fly dynamics; excited states; proton transfer mechanism



Author: Adélia J. A. Aquino - ; Institute for Theoretical Chemistry, University of Vienna, Waehringerstrasse 17, A-1090 Vienna, Austria

Source: http://hrcak.srce.hr/



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