Title:
Tutorial example - photo-electron spectra of hydrogen
The purpose of this exercise is to
(1) guide you to approaching realistic calculations
- tune the basis,
- tweek the time-propagation
- assess accuracies
[TASK] run Spectrum, inspect the spectra
[TASK] try without cutEnergy - see how much slower it is
[TASK] perform another calculation with absorption starting only at 30 au
vary the basis, from comparisons, assess the result
[TASK] move the Surface to 25 and 30 au, compare
[TASK] compare with a calculation whithout trunc[15,20] - assess error due to Coulomb tail
# Rc - where to pick up the surface flux
Surface: points
20.
# basis comparatively small, to get results quickly
Axis: name,nCoefficients,lower end, upper end,functions,order
Rn,40, 0.,20.,polynomial,20
Rn,20, 20.,Infty,polExp[1.]
Phi,1
Eta,4,-1,1, assocLegendre{Phi}
Absorption: kind, axis, theta, upper
ECS,Rn,0.3,20.
# potential in the Hamiltonian - as in 1d, we clip the Coulomb tail off
Operator: hamiltonian='1/2<>-<1><1>'
Operator: interaction='iLaserAz[t]<>'
Operator: expectationValue='<1><1>'
Laser: shape, I(W/cm2), FWHM, lambda(nm)
cos2, 1.e15, 8. OptCyc, 20.
# cutEnergy ...impose a spectral cut on the Hamiltonian
this essential to speed up up the time-propagation
# store ...we save the surface values and derivatives at a fine time grid (au)
TimePropagation: begin,end,print,store,cutEnergy,accuracy
-8 OptCyc, 20 OptCyc, 0.5 OptCyc,0.05 au,30,1.e-10
# NOTE: the stop time is rather long after the pulse
we need to wait until all flux has left through the surface
propagation after the pulse is off is usually cheap, one can be generous here