Time-dependent close-coupling method for excitation of hydrogen

We studied atom excitation by strong laser pulses in dipole approximation. The excitation probability of the hydrogen atom is calculated using a set of time-dependent close-coupling differential equations. Our close-coupling equations include up to six channels from 1S to 3P states. The calculated excitation probability dependence of the 2P and 2S states on the laser frequency is in good agreement with the results obtained in [8].