Chemical Reaction on the Born-Oppenheimer surface and beyond ISSP Osamu Sugino FADFT WORKSHOP 26 th...
-
Upload
valentine-mccoy -
Category
Documents
-
view
218 -
download
0
Transcript of Chemical Reaction on the Born-Oppenheimer surface and beyond ISSP Osamu Sugino FADFT WORKSHOP 26 th...
-
Chemical Reactionon the Born-Oppenheimer surface and beyondISSPOsamu SuginoFADFT WORKSHOP 26th July
-
Chemical ReactionOn the (ground state) Born-Oppenheimer surfaceThermally activated process: ClassicalBeyond: excited state potential surfaceNon-adiabatic reaction: QuantumDissipation (dephasing): Classical aspect
-
Chemical Reactions on the BO surfacePotential energy surfaceSearch for reaction path and determine the rate
A+BC
-
Thermally activated processReaction coordinate
Transition State Theory (TST) (1935~)Thermodynamic treatmentBoltzmann factorTransition stateQ
-
Other degrees of freedomQ0eqTSH0H1H(Q)1Thermodynamic integration
-
Thermodynamic integration
-
1. Thermodynamics second low2. Jarzynskis identity(JCP56,5018(1997))cf. Fast growth algorithmOther topics related to the free-energy:To be presented at FADFT Symposium presentations by Y. Yoshimoto (phase transition) Y. Tateyama (reaction)
-
Free-energy vs. direct simulationFree-energy approachTS and Q need to be defined a priori
Direct simulationThe more important the more complex
Solvated systemsWater fluctuatesRetarded interaction (dynamical correlation)
-
An example of the direct simulationChemical reaction at electrode-solution interfaceTo be presented by M. Otani, FADFT Symposium
-
H3O++eH(ad)+H2ORedox reaction at Pt electrode-water interfaceHydronium ion (H3O+) acid conditionExcess electrons (e) negatively biased conditionVolmer step of H2 evolution electrolysisH2OPt350K, BO dynamics
-
H3O++eH(ad)+H2OPtH2ORedox reaction at Pt electrode-water interfaceHydronium ion (H3O+) acid conditionExcess electrons (e) negatively biased conditionVolmer step of H2 evolution electrolysis
-
First-Principles MD simulationPtH2OH3O+ deficit in electronsPt excess electronsH3O+QFH3O++eH(ad)+H2Ovoltage
-
H gets adsorbed and then water reorganizesToo complicated to be required of direct simulation
-
Chemical reaction beyond BONon-adiabatic dynamics
-
Adiabaticity consideration QFH3O++eH(ad)+H2OElectrons cannot perfectly follow the ionic motionDeviation from the Born-Oppenheimer picture
-
adiabaticNon-adiabaticity
-
Wavefunction at t+dt
-
Non-adiabaticity is proportional to the rate of change in HWhile it is reduced when two eigenvalues are differentV1(r)V2(r)Overlap with adiabatic state
-
Born-Oppenheimer TheoryAdiabatic baseDensity matrixEq. of motion
-
A representation of the density matrixEffective nuclear HamiltonianPotential surfaces e and non-adiabatic couplings are required
-
Semiclassical approximation using the Wigner representationNuclear wavepacket
-
Semiclassical wavepacket dynamics requires first order NACsSemiclassical wavepacket dynamics
-
An Ehrenfest dynamics simulationPotential energy surfacedistance from the surface excitationdecaySi-H Si-H *SiH
-
()8-layer slab(2x2) unit cellDeviates from BOs*-electrons-holeY. Miyamoto and OS (1999)
-
How to compute NACTDDFT linear response theoryTo be presented by C. Hu, FADFT Symposium
-
How to derive NAC in TDDFT?The sum-over-states (SOS) representation gives Chernyak and Mukamel, JCP 112, 3572 (2000). Hu, Hirai, OS, JCP(2007)Apply an artificial perturbation and see the response
-
NAC of H3 near the conical intersection123zxO
-
Full Quantum SimulationTo be presented by H. Hirai, FADFT Symposium
-
SummaryChemical reaction (phase transition, atomic diffusion)Free-energy approach has become more and more accessibleDirect simulation is very importantNon-adiabatic dynamicsStill challenging but progress has been made for system with few degrees of freedom
High temperature, heavy element; practically the most important*