Title:
Tutorial example - spectra from 1d hydrogen in a laser field
The purpose of this exercise is
(1) see how spectra are calculated in a simple case
(2) understand the paremeter requirements
(3) confirm your expectations on a multi-photon peak
[TASK] run ./Spectrum tutorial/08Hyd1dSpectrum/00xx, inspect the spectra
check Spectrum.doc for input options (after you run it for the first time)
[TASK] check sensitivity to spatial discretization:
you will see that the present discretization is rather generous
[TASK] vary intensities, confirm the multi-photon character of the peaks you see
[TASK] shorten the time-integration in the spectral integration
./Spectrum tutorial/08Hyd1dSpectrum/00xx -tMax=[your choice in atomic units]
What is the effect on the spectrum?
[TASK] relax time-propagation accuracy see what happens
# surface values and derivatives will at X=20 will be written to file
Surface: points
20.
# laser pulse parameters: cos2 pulse
Laser: shape, I(W/cm2), FWHM, lambda(nm)
cos2, 2.e14, 10. OptCyc, 20.
# time-progation
# from start of the pulse (default)
# to many optical cycles (long after the field is gone)
# print output at the given intervals
TimePropagation: end,print,store,accuracy
100 OptCyc, 1. OptCyc,0.,1.e-11
# NOTE: we have given here a very small tolerance value for accuracy
this is mostly to force the self-adaptive time-integrator to write
many steps to file for the integration of the high-freuqency oscillations
of the surface
Absorption: kind, axis, theta, upper
ECS,X,0.5,20.
# piece-wise specification of discretization with exponential tails at both ends
Axis: name,nCoefficients,lower end, upper end,functions,order
X, 20,-Infty,-20.,polExp[1.]
X, 80,-20.,20.,polynomial,20
X, 20, 20.,Infty,polExp[1.]
# potential in the Hamiltonian:
# for tSurff, there is an error by the long range Coulumb outside the tSurff radius Rc
# we may just as well clip that tail off and solve a slightly different problem using trunc[15,20]
# for such a problem, tSurff is exact
Operator: hamiltonian='0.5-'
# interation with the 0 component of a laser field in velocity gauge
# the time-dependent factor is the vector potential A(t)
Operator: interaction='iLaserA0[t]<1_d>'
# monitor and also write to file
# the expectation value of the characteristic function in [-5,5] and [-10,10]
Operator: expectationValue=''