| Description |
Guided ion beam tandem mass spectrometry (GIBMS) is used to probe the kinetic energy dependences of protonated hydrazine colliding with Xe, proton-bound hydrazine and unsymmetrical 1,1-Dimethylhydrazine (UDMH) clusters and protonated hydrazine and UDMH clustered with water colliding with Ar. The resulting cross sections are analyzed using a statistical model after accounting for internal and kinetic energy distributions, multiple collisions, and kinetic shifts to obtain 0 K bond dissociation energies (BDEs) for the threshold collision induced dissociation (TCID). The dominant dissociation pathways for protonated hydrazine (N2H5+) and its perdeuterated variant (N2D5+) were the observed endothermic non-adiabatic homolytic and heterolytic N-N bond cleavages forming NH 3+(2A2'') + NH2(2A1) and NH2+( 1A1) + NH3(1A 1), respectively. For the proton-bound clusters, the primary dissociation pathways for (N2H4)nH+ where n = (2-4) and (UDMH)2H+ consists of a loss of hydrazine or UMDH unit, followed by the sequential loss an additional hydrazine at higher energies for n > 2. As to be expected, a similar trend is observed for the primary dissociation pathways for (N2H4)H +(H2O)n where n = ( 2 and 3) and (UDMH)H+(H2O) where the losses of a water unit are followed by the sequential loss of a water unit for n ≥ 2. A larger GIBMS is used to probe the association reactions below 1 eV, of Fen+ + CO where n = 4-17. All clusters where n ≥ 4 form the FenCO+ association complex; the resulting cross sections are analyzed using a statistical model after accounting for internal and kinetic energy distributions, multiple collisions, and kinetic shifts to obtain 0 K binding energies for CO binding to iron cluster cations. The probability of this reaction increases with cluster size until the absolute cross sections equal the collision limit for n > 10, with those for n = 12 and 14 exceeding the collision limit. For the largest clusters, the binding energies approach that of an extended Fe(111) surface, whereas the prominent higher energy feature correlates to binding energies for dissociatively chemisorbed C and O on an iron surface. |
