Dissociative recombination of OPCl+ and OPCl2+: Pushing the upper mass limit at CRYRING

Abstract

The public reporting burden for this collection of Information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing the burden to Department of Defense, Washington Headquarters Services Directorate for Information AFRL-RV-HA-TR-2008-1145 SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR'S ACRONYM(S)AFRL/RVBXT SPONSOR/MONITOR'S REPORT NUMBER(S)12. DISTRIBUTION/AVAILABILITY STATEMENT ABSTRACTThe dissociative recombination of OPCl + and OPCI 2 + has been studied at the storage ring CRYRING. The rate constants as a function of electron temperature have been derived to be 7.63 * I0" 7 (7* ( ,/300)" 08 ''and >l/2 « 10-6 (7^300)"' 22 cm 3 s"'. respectively. The lower limit quoted for the latter rate constant reflects the experimental inability to detect all of the reaction products. The branching fractions from the reaction have been measured for OPC1+ at =0 eV interaction energy and are determined to be N(0+P+C1)=( 16±7), N(0+PC1)=( 16±3)% and N(OP+Cl)=(68±5)%. These values have been obtained assuming that the rearrangement channel forming P+CIO is negligible, and ah initio calculations using GAUSSIAN03 are presented for the ion structures and energetic to support such an assumption. Finally, the limitations to using heavy ion storage rings such as CRYRING for studies into the dissociative recombination of large singly charged molecular ions are dliscussed. + has been studied at the storage ring CRYRING. The rate constants as a function of electron temperature have been derived to be 7.63 X 10-7 (7y SOO)-0 -8 ' and > 1.2 X 10" 6 (7 e /300) -1 n cm 3 s" 1 , respectively. The lower limit quoted for the latter rate constant reflects the experimental inability to detect all of the reaction products. The branching fractions from the reaction have been measured for OPCl + at ~0 eV interaction energy and are determined to be JV(0 + P+C1) = (16± 7)%, A/(0+PCl) = (16± 3)% and MOP +C1) = (68±5)%. These values have been obtained assuming that the rearrangement channel forming P + CIO is negligible, and ab initio calculations using GAUSSIAN03 are presented for the ion structures and energetics to support such an assumption. Finally, the limitations to using heavy ion storage rings such as CRYRING for studies into the dissociative recombination of large singly charged molecular ions are discussed. SUBJECT TERMS

Experimental studies of the dissociative recombination processes for the dimethyl ether ions CD3OCD$_{2}^{+}$ and (CD3)2OD+

“…The phenomenon has been observed for several polyatomic ions see e.g. Vigren et al (2008); Jensen et al (1999);Zhaunerchyk (2008).…”

“…C 3 H + 7 (Ehlerding et al 2003), DCCCND + (Geppert et al 2004a), POCl + (Zhaunerchyk et al 2008) and DOCO + (Geppert et al 2004b).…”

“…For a two-body breakup channel this can be solved analytically. For the three-body breakup case a similar approach as Müller & Cosby (1999), Thomas (2008) and Zhaunerchyk (2008) was used. For each reaction channel a large amount of DR events were numerically simulated where the energy distribution as well as the direction of the outgoing fragments are randomized (fulfilling energy and momentum conservation laws).…”

Dissociative recombination and mutual neutralization of heavier molecular ions: C10H8+, WF5+, and CnFm+

“…It has been speculated that DR rate coefficients of polyatomic ions Y + n increase with n, for example, OPCl + n or O + n . 8 The present results do not provide a trend for comparison; however, a detailed understanding of the production pathways for WF 3 + and WF 4 + would allow determination of their DR rate coefficients.…”

“…1 The upper mass limit in magnetic rings, however, is approximately 100 Da, due to the fact that heavier ions have lower velocities for stable orbits and then achieving velocity-matching conditions is extremely difficult. 8 The more recent electrostatic ion storage rings 1, [9][10][11] and traps [12][13][14] can overcome the mass limit because they do not fight the velocitydependent Lorentz force, but only a handful of DR (and no MN) measurements have been taken with these relatively new apparatuses. 9,15 Additional electrostatic storage rings and a) E-mail: afrl.rvborgmailbox@kirtland.af.mil traps are currently being developed.…”