A @F02506@ reaction may be written: \[\text{M}_{1}^{+}\rightarrow \text{M}_{2}^{+}+\text{M}_{3}\] The @D01547@ of a @M03872@ ion of mass-to-charge ratio \(\frac{m_{1}}{z_{1}}\) into an ion of mass-to-charge ratio \(\frac{m_{2}}{z_{2}}\) after electric @A00051@ of the @M03872@ ion and before magnetic deflection gives rise to a peak in the @M03749@ at an apparent mass, \(\frac{m_{2}^{2}\ z_{1}}{m_{1}\ z_{2}^{2}}\). The symbol \(m^{*}\) should be used to indicate the apparent mass of the product ions giving rise to this peak. Traditionally, the peak itself has been called a @M03872@ peak and this should preferably be expressed as @M03874@ peak. It is nevertheless recommended that the former term should be retained. The word @M03872@ should never be used as a noun. Its use as an adjective should be limited to such terms as @M03872@ ion, where it is used correctly, and to the special case of @M03872@ peak discussed above. It should never be used in such terms as @M03872@ reaction, @M03872@ @D01547@, @M03872@ studies, etc. It should be clear that the @M03872@ ion is the ion that undergoes @F02506@; it is not detected. When a reaction is written with an asterisk above the arrow as shown: \[\text{M}_{1}^{+}\overset{\text{*}}{\rightarrow }\text{M}_{2}^{+}+\text{M}_{3}\] this means that the reaction has been confirmed by the observation of a @M03872@ peak. The textual description of such a process may be written as, for example, (\(m^{*}\), \(43\rightarrow 28\), calcd. 18.2, obsd. 18.3) meaning 'for the @F02506@ \(\frac{m}{z}\ 43\rightarrow \frac{m}{z}\ 28\) a @M03872@ peak at \(\frac{m}{z}\) 18.3 (calculated 18.2) has been observed'.