COLL 48 |
| Steven Baldelli and Selimar Rivera. Department of Chemistry, University of Houston, Houston, TX 77204 |
| Sum frequency generation vibrational spectroscopy was used to determine the orientation of the cations in a room-temperature ionic liquid at the air-liquid interface. The ionic liquid studied was 1-butyl-3-methylimidazolium bis-trifluoromethylsulfonimide, [BMIM]+[imide]-. The orientation of the cation, [BMIM]+, was studied as a function of water pressure in the vapor over the range of 10-5 to 200 Torr. At water pressures below 10-4 Torr, the imidazolium ring was oriented parallel to the surface plane. On increasing the water pressure to above 10-4 Torr, the imidazolium ring tipped up from the surface with an angle along the surface normal of 40-55°. No water signal was observed in the spectra at the water pressures studied here. Results at the air-liquid interface are compared with results at the solid-liquid interface. |
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Vibrational Analyses of Dry and Wet Surfaces
2:00 PM-5:45 PM, Sunday, March 28, 2004 Marriott -- Grand Ballroom H, Oral
Division of Colloid and Surface Chemistry |