Charge
inversion processes of the types:
or
respectively, occuring in a collision cell (containing a gas, X) located in a field-free
region preceding a magnetic and electric sector combination placed in either order,
may be detected as follows. If the instrument slits are wide, and if the connections
to the two sectors, appropriate to
transmission of either positive or negative main-beam ions, are simply reversed, the negative
or positive product ions of the two processes, respectively, will be transmitted.
If the magnetic field is scanned, a spectrum of such product ions will be obtained,
and this spectrum is called a charge-
inversionmass spectrum. These spectra are sometimes referred to as −
E and +
E spectra, respectively. The terms '
2E, E/2, −E or +Emass spectrum' should not be used without prior explanation of the meaning 2
E,
E, +
E or −
E.
Source:
PAC, 1991, 63, 1541
(Recommendations for nomenclature and symbolism for mass spectroscopy (including an
appendix of terms used in vacuum technology). (Recommendations 1991))
on page 1551
