Shape-Amplitude Representation of $N$-Particle Photofragmentation Processes

The general form of the multiparticle photofragmentation matrix element in dipole approximation is derived. Using two noncolinear momentum vectors to create a coordinate system enables the extraction of shape amplitudes depending only on lengths and mutual angles of the momentum vectors, i.e., on body fixed quantities, defining the fragmentation configuration. This is in contrast to previous parametrizations and, in particular, allows selection rules to be derived in a simpler and more transparent way.

Figure 1

The vectors appearing in Eq. (3).

Figure 2

${\mathrm{H}}_2$ PDI cross sections for $E_a=E_b=10\mathrm{e}\mathrm{V}$. The dots mark the emission direction of the electrons. The coordinate system used is shown also.