Collisional activation of pyrene and anthracene in an ion-trap mass spectrometer

A quadrupole ion-trap mass spectrometer (ITMS) has been used to examine internal energy disposition and fragmentation pathways of ionized pyrene and anthracene. Through multiple collisional activation steps, large amounts of energy (tens of electrovolts) can be deposited and multiple-stage (MS{sup n}) dissociation reactions such as C{sub 16}H{sub 10}{sup {sm_bullet}+}{r_arrow}C{sub 16}H{sub 9}{sup +}{r_arrow}C{sub 16}H{sub 8}{sup {sm_bullet}+}{r_arrow}C{sub 14}H{sub 6}{sup {sm_bullet}+}{r_arrow}C{sub 12}H{sub 4}{sup {sm_bullet}+}{r_arrow}C{sub 8}H{sub 2}{sup {sm_bullet}+}{r_arrow}C{sub 3}H{sub 2}{sub {sm_bullet}+} are observed. This particular reaction sequence requires approximately 29 eV, as estimated from the energy requirements for the individual dissociation reactions. While each individual reaction has an activation energy