Spectroscopy, Photophysics and Photochemistry
· Laser photophysics and photochemistry: investigating specially designed bichromophoric molecules elucidates the mechanism of short-range intramolecular electronic energy transfer. The transfer efficiency is studied, in solution, as a
function of excitation energy, temperature and molecule geometry. Complementary calculations and modeling enable elucidation of the transfer mechanism and relation of the model to existing energy transfer theories.
We also study photoconductivity of polymers.
· Spectroscopy and photophysical processes in supersonic jets: Using a supersonic beam expansion technique, the
spectroscopy and photophysics of bichromophoric molecular clusters and molecules are being studied. The processes under investigation are at an electronic energy transfer, quenching of excited states by molecular oxygen, exciplex formation and electron transfer processes.
· Molecular nonlinear optics, optoelectronics and molecular electronics: We have developed a powerful theoretical model, the nonlinear eikonal approximation, to study practical molecular optoelectronic devices either in thin film or in waveguide structures, such as optical fibers. Bistable optical devices, spatial light modulators, molecular memory devices and propagation effects in optical fibers have been analyzed in detail. More recently we study molecular
structure control of intramolecular electron, proton and energy transfer processes and their implications in design of molecular switches and molecular scale logic gates.
· Laser Material Interactions: In collaboration with industry and the Israel Institute of Metals we investigate the mechanism of laser induced deposition of thin films and laser induced removal of contaminates from silicon wafers.
1. S. Speiser and S. Kimel: "Laser-induced photolysis of iodoform", J. Chem. Phys., 51,
2. R. Katraro, A. Ron and S. Speiser: "Photophysical studies of coronene and 1,12 benzperylene; Self-quenching,
photoquenching temperature dependent fluorescence decay and temperature dependent electronic energy transfer
to dye acceptors", Chem. Phys. 42, 121-132 (1979).
3. D. Getz, A. Ron, M.B. Rubin and S. Speiser: "Dual fluorescence and intramolecular energy transfer in a bichromophoric molecule", J. Phys. Chem. 84, 768-773 (1980).
4. M.T. Duignan, E. Grunwald and S. Speiser: "Infrared multiphoton photochemistry of hexafluorobenzene studied
by time-resolved luminescence spectroscopy", J. Phys. Chem. 87, 4387-4394 (1983).
5. S. Hassoon, H. Lustig, M.B. Rubin and S. Speiser: "The mechanism of short range intramolecular electronic
energy transfer in bichromophoric molecules", J. Phys. Chem. 88, 6367-6374 (1984).
6. M. Orenstein, S. Speiser and J. Katriel: "A general eikonal treatment of coupled dispersively nonlinear resonators
exhibiting optical multistability", IEEE J. Quant. Electron. 21, 1513-1522 (1985).
7. S. Speiser and F.L. Chisena: "Optical bistability in dye molecules", J. Chem. Phys. 89, 7259-7267 (1988).
8. S.-T. Levy, M.B. Rubin and S. Speiser: "Photophysics of cyclic a-diketone aromatic ring bichromophoric
molecules. Structures, spectra and intramolecular electronic energy transfer", J. Am. Chem. Soc., 114, 10747-56
9. J. Bigman, Y. Karni and S. Speiser: "Electronic energy transfer in bichromophoric molecular clusters", Chem.
Phys., 177, 601-617 (1993).
10. G. Rosenblum and S. Speiser: "Calculation of intermolecular interaction in aromatic molecular clusters from direction dependent atom-pair potentials", J. Chem. Phys. 102, 9149-9159 (1995).
11. Y. Greenwald, G. Cohen, J. Poplawski, E. Ehrenfreund, S. Speiser, and D. Davidov: "Transient photoconductivity of acceptor substituted poly(3-butyl)thiophene" , J. Am. Chem. Soc., 118, 2980-2984 (1996).
12. N. Lokan, M.N. Paddon-Row, T.A. Smith, M. La Rosa, K.P. Ghiggino and S. Speiser: “Highly efficient through-bond-mediated electronic excitation energy transfer taking place over 12Å”, J. Am. Chem. Soc., 121,
13. X. Wang, D.H. Levy, M.B. Rubin and S. Speiser: "Supersonic jet spectroscopy and intramolecular electronic energy transfer in naphthalene-(CH2)n-anthracene bichromophoric molecules", J. Phys. Chem., 104, 6558-6565 (2000).
14. F. Remacle, S. Speiser and R.D. Levine: "Intermolecular and intramolecular logic gates", J. Phys. Chem. B, 105, 5589-5591 (2001).
15. M. Hagesawa, S. Enomoto, T. Hoshi, K. Igarashi, T. Yamazaki, Y. Nishimura, S. Speiser and I. Yamazaki, "Intramolecular excitation energy transfer in bichromophoric compounds in stretched polymer films", J. Phys. Chem. B., 106, 4925-4932 (2002).
16. U. Peskin, M. Abu-Hilu, S. Speiser: “Approaches to molecular devices based on controlled intramolecular electronic energy and electron transfer. Electron transfer through flexible molecular bridges by a time-dependent super exchange model”, Opt. Mat. 24, 23-29 (2003).
17. H. Salman, Y. Abraham, S. Meltzman, S. Tal, M. Kapon, N. Tessler, S. Speiser and Y. Eichen: “1,3-di(2-pyrrole)azulene: An efficient luminescent probe for fluoride”, Eur. J. Org. Chem., 2005, 2207-2212.
18. H. Salman, Y. Eichen, and S. Speiser:” A molecular scale full adder based on controlled intramolecular electron and energy transfer”, Mat. Sci. Eng. C 26, 881-885 (2006).
19. T. Nakabayashi, B. Wu, T. Morikawa, T. Iimori, M. B. Rubin, S. Speiser, and N. Ohta :” External electric field effects on absorption and fluorescence of anthracene-(CH2)n-naphthalene bichromophoric molecules doped in a polymer film”. J. Photochem. Photobiol. A: Chem. 178, 236-241 (2006).
20. N. Fridman, M. Kaftory, Y. Eichen, and S. Speiser:”Spectroscopy, photophysical and photochemical properties of bisimidazole derivatives“, J. Photochem. Photobiol. A: Chem. 188, 25-33 (2007)
21. O. Kuznetz, D. Davis, H. Salman, Y. Eichen, and S. Speiser :”Intramolecular electronic energy transfer in rhodamine-azulene bichromophoric molecule” ,J. Photochem. Photobiol. A: Chem. 191,176-181 (2007)
22. O. Kuznetz, H. Salman, N. Shakkour, Y. Eichen, and S. Speiser:“ A novel all optical molecular scale full adder ”, Chem. Phys Letters, 451 , 63-67 (2008)
23. O. Kuznetz, H. Salman, Y. Eichen, F. Remacle, Rd. Levine, and S. Speiser:“ All optical full adder based on intramolecular electronic energy transfer in the rhodamine-azulene molecular system”, J. Phys. Chem. C , 112, 15880-15885 (2008).
D. Davis., M. Caspary Toroker, S. Speiser, and U.Peskin: ”On the effect of nuclear bridge modes on electronic tunneling in donor-bridge-acceptor molecules”,
24. S. Speiser:”Prospects of luminescence based molecular logic gates and scale logic circuits", J. Luminesc. 169B, 458-465 (2016)