I have done a real time simulation for a material. For a DELTA field and for small field (1000 kw/cm2), My absorption spectrum using ypp_rt looks like equilibrium spectrum. I would like to study the behaviour by applying strong field . For the integrator RK2, NAN value in the polarisation is observed. When I use the following parameters (i-iii) and do the real time calculation. I got the polarisation profile correct. However, ypp_rt does not give the correct absorption spectrum rather it gives a very strange kind.
i) the QSSIN field with field intensity of (4000000 kw/cm2)
ii) Field1_frequncy = excitation frequency from the equilibrium spectrum
iii) Integrator RK4
Other parameter is given below.
Code: Select all
% RTBands 33 | 52 | # [RT] Bands % Integrator= "RK4" # [RT] Integrator. Use keywords space separated ( "EULER/EXPn/INV" "SIMPLE/RK2/RK4/HEUN" "RWA") PhLifeTime=100.000000 fs # [RT] Constant Dephasing Time RTstep= 0.00100000 fs # [RT] Real Time step length NETime=260.000000 fs # [RT] Simulation Time % IOtime 2.000000 | 1.000000 | 0.100000 | fs # [RT] Time between two consecutive I/O (CARRIERs - GF - OUTPUT) % % Field1_Freq 0.751000 | 0.75100 | eV # [RT Field1] Frequency % Field1_Int=4000000.000000 kWLm2 # [RT Field1] Intensity Field1_Width=43.000000 fs # [RT Field1] Width Field1_kind= "QSSIN" # [RT Field1] Kind(SIN|RES|ANTIRES|GAUSS|DELTA|QSSIN) Field1_pol= "linear" # [RT Field1] Pol(linear|circular)