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(2.3) |
Where,
m
m2+ + m3, (m2 is the mass of the daughter ion detected, m3 is the mass of the other fragment),
E is the energy release recorded in the lab (calculated from the FWHM of the momentum release), E is the energy of the daughter ions and
is the acceleration voltage.
The profiles of energy releases yield valuable information about the upper state of a particular transition. Fragment ions can be thought of as ejected parallel or perpendicular to the laser polarisation, depending on whether J= 0 (a Q transition) or
J=
1 (P and R transitions) were induced. Fragment ions arising from a Q transition are oriented along the ion beam axis more strongly than fragments arising from a P or R transition (orientated along the laser polarisation axis). In a fast ion beam laboratory experiment which records energy (or momentum) releases using an electron multiplier, Q lines are observed as a doublet (or in the case of lower resolution, a small dip in the centre of the profile), whereas P or R lines exhibit a singlet profile [4].