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The Landau-Teller model revisited

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Presentation on theme: "The Landau-Teller model revisited"— Presentation transcript:

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2 The Landau-Teller model revisited
Tim Wendler and Manuel Berrondo BYU Physics

3 Quantum-Classical coupling Lie algebraic solution 6 coupled equations
I am calculating the dynamics of a collinear atom/diatomic molecule inelastic collision Jacobi coordinates Quantum-Classical coupling Lie algebraic solution 6 coupled equations Canonical ensemble

4 Collinear Configuration
Diatomic molecule Atom Harmonic oscillator potential for BC Repulsive interaction for AB No AC interaction Energy is in units of Valid for

5 Jacobi Coordinates 1 2

6 Potential Energy Surface

7 Equations of motion Classical for Translation Quantum for vibration
Expansion Classical for Translation Quantum for vibration

8 Expanded and Rearranged
Quantum Hamiltonian “dipole” term Expanded and Rearranged Quantum for vibration

9 Time Evolution Operator
Constant ket Quantum equation of motion for vibration

10 Lie Algebraic Approach
Time dependence goes into “c” numbers

11 Nuances End up with terms like Utilize Berrondo anti-symmetric product
Very general and useful equation End up with terms like Utilize Berrondo anti-symmetric product

12 Not operator equations!
6 coupled equations Not operator equations!

13 Transition Rates Initial conditions

14 Phase Space Calculations
Initial conditions

15 Intuitive plot of collision
New Trajectory

16 Classical Comparison Quantum phase gained energy Classical phase lost energy Same until initial speed passes the max oscillator speed Certain phase relations result in opposite effects

17 A density matrix can represent a statistical mixture of pure states.
Mixed States A superposition is in both states A mixture is in perhaps one or perhaps the other No interference A density matrix can represent a statistical mixture of pure states.

18 Quantum Liouville Equation
Initial state in equilibrium at temperature T Just after the collision In principle, isolated quantum systems are very non-ergodic, and one must couple them to the outside world to induce transitions between the many-body Eigenstates needed for equilibrium.

19 Out of equilibrium, for the moment
A canonical ensemble of oscillators Non-equilibrium Initial State of canonical ensemble at Temperature T Just after collision, thermal equilibrium is lost

20 General boson algebra coefficients already calculated!
Summary No wave functions A simple equation standard Phase Space Transition Rates Canonical Ensemble Infinite order transitions Specific system input General boson algebra coefficients already calculated!

21 Oxidation of methyl esters
Future – Reactive Collisions SN2 Reactions Nuclear Reactions Oxidation of methyl esters


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