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Primary Event in Vision

Primary Event in Vision. Ultrafast Photo-Isomerization Mechanism. Technological applications: associative memory devices. R.R. Birge et.al. J. Phys. Chem. B 1999 ,103, 10746. Femto-second Spectroscopic Measurements. ONIOM QM/MM B3LYP/631G*:Amber. QM Layer (red): 54-atoms.

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Primary Event in Vision

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  1. Primary Event in Vision

  2. Ultrafast Photo-Isomerization Mechanism

  3. Technological applications: associative memory devices R.R. Birge et.al. J. Phys. Chem. B1999,103, 10746

  4. Femto-second Spectroscopic Measurements

  5. ONIOM QM/MM B3LYP/631G*:Amber QM Layer (red): 54-atoms MM Layer (red): 5118-atoms EONIOM =EMM,full+EQM,red -EMM,red Boundary Ca-Cd of Lys296

  6. Reaction Path: negative-rotation

  7. Reaction Energy Profile:QM/MM ONIOM-EE (B3LYP/6-31G*:Amber) all-trans bathorhodopsin Intermediate conformation Exp Value : * 11-cis rhodopsin Energy Storage Dihedral angle

  8. Intermediate conformation all-trans bathorhodopsin 11-cis rhodopsin

  9. Isomerization Process C13 H2O C11 C12 N Glu113

  10. Superposition of Rhodopsin and Bathorhodopsin in the Binding-Pocket: Storage of Strain-Energy

  11. Charge-Separation Mechanism Reorientation of Polarized Bonds H H

  12. Electrostatic Contribution to the Total Energy Storage 62% Energy Storage[QM/MM ONIOM-EE (B3LYP/6-31G*:Amber)] - Energy Storage[QM/MM ONIOM-ME(B3LYP/6-31G*:Amber)] Electrostatic Contribution of Individual Residues

  13. TD-DFT Electronic Excitations ONIOM-EE (TD-B3LYP/6-31G*:Amber) DE rhod. DE batho. DDE Values in kcal/mol 63.5 60.3 3.2 TD-B3LYP//B3LYP/6-31G*:Amber 64.1 CASPT2//CASSCF/6-31G*:Amber 57.4 54.0 3.4 Experimental

  14. Time-Sliced Simulations of Quantum Processes

  15. Trotter Expansion MP/SOFT Method Wu,Y.; Batista, V.S. J. Chem. Phys. 118, 6720 (2003) Wu,Y.; Batista, V.S. J. Chem. Phys. 119, 7606 (2003) Wu,Y.; Batista, V.S. J. Chem. Phys. 121, 1676 (2004) Chen, X., Wu,Y.; Batista, V.S. J. Chem. Phys. 122, 64102 (2005) Wu,Y.; Herman, M.F.; Batista, V.S. J. Chem. Phys. 122, 114114 (2005) Wu,Y.; Batista, V.S. J. Chem. Phys.(2006) 124, 224305 Chen, X.; Batista, V.S. J. Chem. Phys.(2006) 125, 124313 Chen, X.; Batista, V.S. J. Photochem. Photobiol. 190, 274-282 (2007)

  16. Bichromatic coherent-control (Weak-field limit)

  17. Quantum interference of molecular wavepackets associated with indistinguishable pathways to the same target state | j > | k > Isomerization coordinate,

  18. Time dependent wavepacket undergoing nonadiabatic dynamics at the conical intersection of S1/S0 potential energy surfaces Chen X, Batista VS; J. Photochem. Photobiol. 190, 274-282 (2007)

  19. Ground vibrational state

  20. First Excited Vibrational State

  21. Bichromatic coherent-control Pulse Relative Phases Pulse Relative Intensities

  22. Bichromatic coherent-control Pulse Relative Phases Pulse Relative Intensities

  23. Bichromatic coherent-control Pulse Relative Phases

  24. The Primary Step in Vision cis/trans isomerization in visual rhodopsin Flores SC and Batista VS, J. Phys. Chem. B (2004) 108: 6745-6749 Gascon JA, Batista VS, Biophys. J. (2004) 87:2931-29411 Gascon JA, Sproviero EM, Batista VS, J. Chem. Theor. Comput. (2005) 1:674-685 Gascon JA, Sproviero EM, Batista VS, Acc. Chem. Res. (2006) 39, 184-193 Chen X and Batista VB, J. Photochem. Photobiol. submitted (2007) 190, 274-282, 2007

  25. Empirical model (Domcke, Stock)

  26. Time dependent reactant population MP/SOFT‡ TDSCF* 0.67 Ptrans(S0) Pcis(S1) Time, fs ‡Chen X, Batista VS; J. Photochem. Photobiol. submitted (2007) *Flores SC and Batista VS, J. Phys. Chem. B (2004) 108: 6745-6749

  27. Quantum interference of molecular wavepackets associated with indistinguishable pathways to the same target state Isomerization coordinate, Flores SC; Batista VS, J. Phys. Chem. B108: 6745-6749 (2004) Batista VS; Brumer P, Phys. Rev. Lett.89, 143201 (2002) | j > | k >

  28. Quantum interference of indistinguishable pathways to the same target state x | xi > | j > | k > | xf > O. Nairz, M. Arndt and A. Zeilinger Am. J. Phys.71, 319 (2003)

  29. Bichirped Coherent Control Scenario Flores SC; Batista VS, J. Phys. Chem. B (2004) 108: 6745-6749 CR = CR= Chirped Pump Pulses (Wigner transformation forms)

  30. Impulsive Stimulated Raman Scattering Energy S1 Reaction coordinate (Stretch. Coord.) NC: PC:

  31. Exact Quantum Dynamics Simulations (t=218 fs, CR=212 fs2) Excited State S1 Ground State S0 cis trans

  32. Positively Chirped Pulse (PC), strong field

  33. Exact Quantum Dynamics Simulations (t=218 fs, CR=-146 fs2) Excited State S1 Ground State S0 cis trans

  34. Negatively Chirped Pulse (NC), strong field

  35. Bichirped Coherent Control Maps (1.2 ps) Pulse Relative Phases Pulse Relative Intensities

  36. Conclusions • We have shown that the photoisomerization of rhodopsin can be controlled by changing the coherence properties of the initial state in accord with a coherent control scenario that entails two femtosecond chirped pulses. • We have shown that the underlying physics involves controlling the dynamics of a subcomponent of the system (the photoinduced rotation along the C11-C12 bond) in the presence of intrinsic decoherence induced by the vibronic activity. • Control over 5-10% product yields should be possible, despite the ultrafast intrinsic decoherence phenomena, providing results of broad theoretical and experimental interest.

  37. Conclusions • We have shown that the ONIOM-EE (B3LYP/6-31G*:Amber) level of theory, in conjunction with high-resolution structural data, predicts the energy storage through isomerization, in agreement with experiments. • We have shown that structural distortions account for 40% of the energy stored, while the remaining 60 % is electrostatic energy due to stretching of the salt-bridge between the protonated Schiff-base and the Glu113 counterion. • We have shown that the salt-bridge stretching mechanism involves reorientation of polarized bonds due to torsion of the polyene chain at the linkage to Lys296, without displacing the linkage relative to Glu113 or redistributing charges within the chromophore

  38. Conclusions (cont.) • We have demonstrated that a hydrogen-bonded water molecule, consistently found by X-ray crystallographic studies, can assist the salt-bridge stretching process by stabilizing the reorientation of polarized bonds. • We have shown that the absence of Wat2b, however, does not alter the overall structural rearrangements and increases the total energy storage in 1 kcal/mol. • We have demonstrated that the predominant electrostatic contributions to the total energy storage result from the interaction of the protonated Schiff-based retinyl chromophore with four surrounding polar residues and a hydrogen bonded water molecule. • We have shown that the ONIOM-EE (TD-B3LYP/6-31G*:Amber//B3LYP/6-31G:Amber) level of theory, predicts vertical excitation energy shifts in quantitative agreement with experiments, while the individual excitations of rhodopsin and bathorhodopsin are overestimated by 10%.

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