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UV/Vis Absorption Experiments on Mass Selected Cations by Counter- Ion Introduction in an Inert Neon Matrix Nathan Roehr University of Florida 67 th International Symposium on Molecular Spectroscopy
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Thanks Dr. Nick Polfer Dr. Martin Vala Dr. Jan Szczepanski Dr. John Eyler Polfer and Eyler Group Ardara Technologies – Randy Pedder Machine and Electronic Shop Physical Chemistry Travel Grant ACSPRF #49572-‐DNI6 67 th Ohio State Symposium of Molecular Spectroscopy Dr. David Moore Ryan Ludwig Alex Hunter Moore Group Members Lehigh UniversityUniversity of Florida
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Outline Matrix Isolation of Mass-Selected Ions Counter-Ion Introduction UF Instrument CO + and SF 6 - Results Lehigh instrument Cu - and Ar + /Kr + Results Summary
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Inert Gas Inlet Cold (4-20K) Cryostat Target 90 or 270 deg Ion Bender Quadrupole Mass Filter Einzel C Einzel B 4 Inlet for Neutral Electron Filament (EI Source) (+) (-) Einzel A (-) 2 1-2 hrs Source of Ionization Mass Analyzer or Mass Filter Electrostatic/Electrodynamic Ion Guides Cold Cryostat Target nA of Ion Current Experimental Set-Up for Matrix Isolation Expts on Mass-Selected Cations
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Other Modifications 5 hh hh CS 2 + Cl - Originally Neglected Cold Metal Bombardment Electron gun Inert Gas Inlet Cryostat Target Only Works for Cations Use of Scavenger And Scavenger Atomic or Molecular Counter Ions It didn’t work Leroi, G. et al,Soc. for Applied Spec. 15, 4 (1991). Counter Ions zxzx + + + Inconsistent Unknown Counter-Ions Throwing Away Ions
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CI Source EI Source Cryostat Window Deflector Quadrupole Mass Filter FT IR UF Instrument CO SF 6 ~5 nA of both CO + and SF 6 - ions 10 V bias 12 hrs of Deposition
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IR Spectra - CO + and SF 6 - Deposition Absorbance Wavenumber / cm -1 2148.8 cm -1 ν m CO 2137.7 cm -1 ν a CO CO + Gas - 2183.9 cm -1 Solid Neon – 2194.4 cm -1 ? Jacox, M.E., Chem. Phys. 189, (1994). 149-170
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David Moore Assistant Professor Alex Hunter Masters Student Ryan Ludwig Grad Student Lehigh University
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UV-Vis CCD Detector UV-Vis Source Quadrupole Ion Guide Quadrupole Mass Filter Octopole Ion Guide EI Source KBr Window Deflector Magnetron Aggregation Region Lehigh Instrument ~3-5 nA of both Cu - and Ar + or Kr + ions 10 V bias 3 hrs of Deposition Cu Target Ar or Kr 20K or 15K Ar
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λ / nm UV Spectra Cu - and Ar + Deposition Absorbance Ozin, G.A. et al, J. Phys. Chem. 86, 473-479 (1982). 300.18 304.22 308.99 Literature Cu Neutral: (4p) 2 P <- (4s) 2 S 299, 302, 306 Thermally Unstable - 319, 323 319.9 323.66 05/25 20K 05/28 λ / nm
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Absorbance 10K 20K 32K 10K 20K 32K λ / nm UV Spectra Comparison 05/2805/25
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Absorbance 20K 26K 32K 50K 100K 300K λ / nm UV Spectra Cu - and Ar + Deposition Akilbekov, A.T. et al, Fiz. Tverd, Tela, 86, 473-479 (1982).
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Absorbance 0.14” Lower Center 0.14” Higher λ / nm UV Spectra Cu - and Kr + Deposition 15K
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Detectable Quantities of Neutral Species Trapped in Solid Argon Deposition Occurred Mostly at the Beam Center Temperature Affected Ratio of Thermally Unstable Bands Summary & Conclusions
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Deposit Neutral Cu to Check Peak Ratio at ~309-310 nm Deposit Cu 2 - into Matrix Introduce O 2 or CO with Matrix Gas to See if Metal Ligand Complexes Form Deposit Cu + to Determine Cation/Neutral Ratio Further Work
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END
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UF Setup
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