Adiabatic theory of strong-field ionization of molecules with nuclear motion

Strong-field ionization

Adiabatic approximation

• Assume field varies slowly
• Laser field momentarily constant
• Sequence of stationary Siegert states

Sequence of stationary states

Objective

Develop adiabatic theory for molecules including nuclear motion

Time-dependent Schrödinger equation

AAnf

Assuming $T_{\text{electron}}\ll T_{\text{field}},T_{\text{nuclei}}$

Born-Oppenheimer ansatz

Photo-electron momentum distribution (PEMD)

Mapping time to momentum

Convergence of PEMD

Channel ionization probabilities

Reflection approximation

Classical turning points

Channel ionization probabilities

Channel ionization probabilities

Acknowledgment

• Prof. T. Morishita
  The University of Electro-Communications
• Prof. O. Tolstikhin
  Moscow Institute of Physics and Technology
• Funding from JSPS

Breakdown of BOA

What we want to look at

• BOA breaks down in weak-field limit for total rate
• WFAT gives total rate
• Adiabatic theory gives differential quantities
• Differential quantities might show other BO-breakdowns

Numerical methods

Split step fourier method

Scattering states found using R-matrix propagation

Time-independent Schrödinger equation

Scattering boundary conditions

Boundary conditions

${\mathrm{\Psi }}_{+}^{\text{out}}(x,k)$

Scattering solution method

• R-matrix propagation in $x$
• Adiabatic basis in $R$ for fixed $x$
• Sectorized legendre DVR in $x$
• Sine-DVR in $R$

Different grids

Time is mapped to momentum

PEMD

Pulse

Build the PEMD

Full wavefunction evolution