Simultaneous Deposition of Mass Selected Anions and Cations: Improvements in Ion Delivery for Matrix Isolation Spectroscopy Michael E. Goodrich and David T. Moore Chemistry Department, Lehigh University Bethlehem, PA 18015

Ion Delivery in Matrix Isolation Intrinsically Neutral Sources Andrews Laser Ablation Jacox Microwave Discharge Secondary Ionization Maier (and my previous talk!) Charge Balance! Our system allows for mass selection of metal anions to be co-deposited with a counter cation beam generated in an EI source Lacked control over counter ion m/z – only EI of atomic gases Ludwig, R. M.; Moore, D. T.; J. Chem. Phys. 2013, 139, 244202.

Improved Ion Delivery Additional chamber containing EI source and additional mass resolving quadrupole Allows for simultaneous mass resolution of deposited anions and cations More complicated counter ion gases can be used – specific fragments can be selected for deposition – SF5+ vs SF3+ for example

Experimental Conditions Deposition Spectrum Deposit 0.02% CO in Ar at 20K at a rate of 10 sccm for 4 hours Co-deposit balanced current of mass selected Cu- and SF5+ or SF3+ (~8 nA of total ion flux) Copper carbonyl system is well characterized – good system to test with new counter ion deposition system

Cation Deposition Conditions SF3+? FCO 55eV SF5+ 22eV SF3+ SF5+ Important to note: Copper carbonyls not affected by counter ion conditions SF5+ not previously identified in Ar – base ID on Jacox in Neon and the mass spec info 22eV SF5+ Anions in the matrix upon deposition , Cu(CO)x-, are not effected by the counter ion deposition conditions Jacox, M. E.; J. Mol. Spectroscopy, 1980, 80, 257.

Tracking Electrons Upon Photodetachment 470 nm LED 590 nm LED Deposition Upon irradiation, electrons released from copper carbonyl complexes attach to SF5+ to form SF5

Difference Spectra: Before and After Irradiation of the Matrix Small Changes in SF5+? Difference Spectra: Before and After Irradiation of the Matrix Electrons are released by anionic copper carbonyl complexes during irradiation SF5+ is converted to SF5 Photodetachment is gentle process , but some SF5 may be generated from SF6 electron attachment

Conclusions and future work Increased control over ionic species present in matrix Cationic signature to track photodetached electrons Principle of duel mass selection can be used to study more interesting ion – ion interactions