Internal energy of stored large molecular anions deduced from laser-induced electron detachment yield

We calculated the internal energy of zinc phthalocyanine anions stored in an electrostatic ion storage ring as a function of a time after their production in a hot source. The relevant experimental data were those obtained for anions heated by a pulsed laser leading to enhancement of the delayed electron detachment signals. We evaluated the energy window of the detectable anions from the lifetime, which enable us to determine the absolute value of the internal energy.