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Calculating Nonlinear Response Functions from Gaussian-Markovian Quantum Fokker-Planck Approach Yoshitaka Tanimura Department of Chemistry Kyoto University
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In an environment ・ Fluctuation ・ Dissipation Chemical processes in condensed phase matched equilibrium Heat bath model
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3 Model Hamiltonian (vibrational modes) T 1 + T 2 relaxationT 2 * relaxation
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In the path integral representation (for a harmonic bath) where is the Feynman-Vernon influence functional. dissipation fluctuation
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QFP equation for Gaussian-Markovian noise bath If we assume we have (colored noise) Markovian like noise For Hamiltonian If temp. is high
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Density matrix elements where Time derivative of each parts are
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we have where Then
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We may evaluate by repeating the differentiation, then where is the density matrix for the element
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in the Wigner representation; For nth member (similar to Kubo‘s stochstic Liouv. Eq.) Quantum Liouvillian is (YT & Kubo, JPSJ 1989)
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G-M quantum Fokker-Planck eq (LL+SL) Quantum Liouvillian YT & Wolynes JCP 1993 YT (review), JPSJ 2006 ↑ temperature term qx (LL) + q 2 x (SL)
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Physica meaning of Hierachy elements Dashed line represents the system-bath interactions (0 th order is exact) Major roles to calc. correlation func. (correlated effects)
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12 Two-time correlation function (Raman spectroscopy) This can be rewritten in the Wigner representation as where A and X stand for the operators and
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13 2D Raman (YT & Mukamel, JCP 1993) two-time variables t 1, t 2 three-body correlation function: is similarly expressed as
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14 Example : anharmonicity 1) Harmonic 2) Morse Quantum Fokker-Planck (white noise at high temperature)
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15 1D Raman 2body correlation func.
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16 2DRaman Three body corre.
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Kaufman, Heo & Fleming, PRL88, 207402(2002). 2D Raman (CS 2 ) Saito and Ohmine, PRL 88, 207401 (2002). Okumura & Tanimura, JCP 107, 2267 (1997) ExperimentMD simulationAnalytical result Anharmonisity + Nonlinear Polarizability
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18 Noise correlation and SL interactions T 1 + T 2 relaxationT 2 * relaxation Hamiltonian
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potential system vs. Energy-level system LL + SL interactions T 1 +T 2 T 2 * different!
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Third-order 2D IR t 2 =0 photon echo signals?
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Linear-Linear and Linear-Square (JPSJ review) Fast modulationSlow modulation only q x j (q+q 2 ) x j only q 2 x j
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2D IR signal of HF liquid (from MD) Hasegawa and Tanimura, submitted to JCP Similar to slow modulation case of LL+SL model
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Low temp. corrections of GM QFP eq. Dissipation Similar to GM caseMatsubara freq. correct. terms High (Matsubara) frequencies terms are approximated by this Fluctuation (former case was )
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Ishizaki and Tanimura, J. Phys. Soc. Jpn. 74, 3134 (2005). GM master eq. with low temp. correction terms
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25 Application to two-mode system Acetylacetonato Rhodiumdicarbonyl(I) (RDC) in chloroform solution Tokmakoff Group@MIT,
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26 “ + ”corr “ - ” corr non corr Anharmonic oscillators coupled with one- or two-bath a single bath two baths
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27 Effects of noise correlation “ + ”corr “ - ” corr non corr Ishizaki and Tanimura, J. Phys. Chem. A (2007)
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Conclusions Quantum Fokker-Planck Eq. for GM noise colored noise, strong system-bath coupling, low temp. (w. low temp. correction terms) Variety of applications (multi-level system, etc) Multi-dimensional spectroscopy critical check for theory Review : Y. Tanimura, J. Phys. Soc. Jpn, 75, 082001 (2006).
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