Time-dependent simulation of the spectrum from a photoionized Si plasma

A time-dependent collisional-radiative model with detailed atomic data is used to model a laboratory photoionized silicon plasma. Time history of emission and absorption coefficients under a Gaussian radiation pulse is presented. The time-integrated spectrum is compared with the experimental one. Without opacity effects, the calculated relative line intensity of the Li-like lines and the He-like resonance line agree well with the measured value while the intercombination line is much weaker than that of the experiment. Taking into account opacity effects may increase the relative intensity of the intercombination line significantly, and the measured line ratio of the intercombination line to the resonance line can be obtained by adjusting the effective optical depth. However, the measured relative line intensities of the Li-like lines, the intercombination line and the resonance line can not be reproduced. It is difficult to understand the high intensity of the intercombination line.