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Published byCelia Pollen Modified over 9 years ago
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Water Solvation of Copper Hydroxide Brett Marsh-UW Madison
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Background Copper Catalytic Relatively cheap Abundant CuOH-Possible water splitting catalyst
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Experiment Electrospray Needle Cryogenic ion trap (10K) For cooling and H 2 -tagging Ion steering optics Flight Tube Reflectron Tunable infrared laser 600-4500 cm -1 Capillary Skimmer Radio-frequency ion guides Ion reaction cell LN 2 cooled (77-350K) Spectroscopy laser Pulsed valves
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Ion Trapping and Tagging H 2 has ideal binding energy (~400 cm -1 typically) and vapor pressure at trap temperature (10 K) H 2 tagging may produce multiply tagged species M.Z. Kamrath, R.A. Relph, T.L. Guasco, C.M. Leavitt, M.A. Johnson, Int. J. Mass. Spec. 2011, 300, 91-98
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Predissociation Spectroscopy E. Garand et. al. Phys. Chem. Chem. Phys., 2012,14, 10109–10113
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Experiment Electrospray Needle Cryogenic ion trap (10K) For cooling and H 2 -tagging Ion steering optics Flight Tube Reflectron Tunable infrared laser 600-4500 cm -1 Capillary Skimmer Radio-frequency ion guides Ion reaction cell LN 2 cooled (77-350K) Spectroscopy laser Pulsed valves
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Results By varying voltages in ion source multiple species of interest can be selected for study
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Results-CuOH(H 2 O) + Addition of 2 nd deuterium tag distorts spectrum Strong H 2 O-D 2 interaction? Multiple conformations for 1 tag complex?
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Results-CuOH(H 2 O) + CAM-B3LYP/6-311+G(d,p) level of theory
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Results-CuOH(H 2 O) 2 + Severe peak suppression occurs after attachment of 2 nd deuterium molecule Possible solvent assisted isomerization?
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Results-CuOH(H 2 O) 2 + Isomers separated by ~1450 cm -1 Multiple lines hidden under same peak? Probe for H-bond stretches (2800- 3100 cm -1 ) CAM-B3LYP/6-311+G(d,p) level of theory
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Solvent Assisted Isomerization Excess solvation energy (in this case from D 2 ) can push the molecule into a more stable well Excess D 2 then evaporates to leave isomer 2+2D 2
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Results-CuOH(H 2 O) 2 + Strong free H 2 O interaction with D 2 tag Theory matches well with experimental spectrum CAM-B3LYP/6-311+G(d,p) level of theory
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Results-CuOH(H 2 O) 2 + CAM-B3LYP/6-311+G(d,p) level of theory
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Results-CuOH(H 2 O) 3 + Addition of 2 nd deuterium tag seems to have no effect on spectrum
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Conclusions Hydrogen tags can not be assumed to offer little perturbation in metal species Attachment of tags may distort the isomeric composition of ions of interest
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Future Work Electrospray Needle Cryogenic ion trap (10K) For cooling and H 2 -tagging Ion steering optics Flight Tube Reflectron Tunable infrared laser 600-4500 cm -1 Capillary Skimmer Radio-frequency ion guides Ion reaction cell LN 2 cooled (77-350K) Spectroscopy laser Pulsed valves Tunable infrared laser 600-4500 cm -1
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Acknowledgements Crim Group Garand Group University of Wisconsin Chemistry Department
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