Double and triple photoionization of Li and Be

We present calculations for the double photoionization (with excitation) and the triple photoionization of Li and Be. We extend and more fully discuss the previous calculations made for Li by Colgan et al. [Phys. Rev. Lett. 93, 053201 (2004)] and present calculations for Be. The Be triple photoionization cross sections are compared with previous double shake-off model calculations of Kheifets and Bray [J. Phys. B 36, L211 (2003)], and our calculations are found to be significantly lower.

Figure 1

(Color online) Double photoionization cross section of Li as a function of photon energy. The total double photoionization cross section is compared with the experiment of Huang et al. [17]. (b) The partial double photoionization cross sections leaving the ${\mathrm{Li}}^{2+}$ ion in one of three possible final states as shown $(1.0\mathrm{kb}=1.0\times {10}^{-21}{\mathrm{cm}}^2)$.

Figure 2

(Color online) Double photoionization cross section of Be as a function of incident photon energy for time-dependent calculations including angular momentum channels up to and including $l=3$. The partial double photoionization cross section leaving the ${\mathrm{Be}}^{2+}$ ion in one of three final states is also shown $(1.0\mathrm{kb}=1.0\times {10}^{-21}{\mathrm{cm}}^2)$.

Figure 3

(Color online) Triple photoionization cross section of Li as a function of incident photon energy. We compare the experiment of Wehlitz et al. [13] with our time-dependent close-coupling calculations. $(1.0\mathrm{b}=1.0\times {10}^{-24}{\mathrm{cm}}^2)$.

Figure 4

(Color online) Time-dependent close-coupling calculations of the triple photoionization cross section of Be as a function of incident photon energy. We compare these calculations with the double shake-off model calculations of Kheifets and Bray [18] (dashed line) $(1.0\mathrm{b}=1.0\times {10}^{-24}{\mathrm{cm}}^2)$.