VUV Spectroscopy of Atoms, Molecules and Surfaces

3.1 Introduction 45
Cross section (arb. units)
200
150
100
50
0
10.92 10.94 10.96 10.98 11.00
600
400
200
0
10.927 10.928
60
(b) (c)
40
20
0
Photon energy (eV)
(a)
10.9550 10.9555
Figure 3.1: (a) Relative photodetachment cross section of D− in the vicinity of the
D(n=2) threshold measured by Andersen et al. [13] and normalized to the theoretical
results of Lindroth [13]. The scanned energy range includes the 2 {0} −
3 and 2 {0}− 4 Feshbach
resonances and the 2 {0} +
2 shape resonace. (b) The 2 {0}− 3 resonance shown on an
enlarged scale, fitted to a Fano profile convolved with a Gaussian function representing the
experimental resolution. (c) The 2 {0} −
4 resonance shown on an enlarged scale, fitted to a
Gaussian function.
of the 2 {0} + 2 shape resonance, which appears non-smooth due to variations in
the laser- and ion-beam overlap. This is a consequence of the large scaling in
ion-beam energy required to scan the relatively broad photon-energy range
covered by this structure. The measured cross section is relative, and each
of the three segments has been normalized to the cross section calculated by
Lindroth and convolved with the experimental resolution (solid curve). The
2 {0}−3 and 2 {0}−4 resonances are shown on an enlarged scale in figures 3.1