Soft Ionization of Thermally Evaporated Hypergolic Ionic Liquid Aerosols
Abstract
Isolated ion pairs of a conventional ionic liquid, 1-Ethyl-3-Methyl-Imidazolium Bis(trifluoromethylsulfonyl)imide ([Emim+][Tf2N-]), and a reactive hypergolic ionic liquid, 1-Butyl-3-Methyl-Imidazolium Dicyanamide ([Bmim+][Dca-]), are generated by vaporizing ionic liquid aerosol nanoparticles for the first time; the vaporized species are investigated by dissociative ionization with tunable VUV light, exhibiting clear intact cations, Emim+ and Bmim+, presumably originating from intact ion pairs. Mass spectra of ion pair vapor from an effusive source of the hypergolic ionic liquid show substantial reactive decomposition due to the internal energy of the molecules emanating from the source. Photoionization efficiency curves in the near threshold ionization region of isolated ion pairs of [Emim+][Tf2N-] ionic liquid vapor are compared for an aerosol source and an effusive source, revealing changes in the appearance energy due to the amount of internal energy in the ion pairs. The aerosol source has a shift to higher threshold energy (~0.3 eV), attributed to reduced internal energy of the isolated ion pairs. The method of ionic liquid aerosol nanoparticle vaporization, for reactive ionic liquids such as hypergolic species, is a convenient, thermally "cooler" source of isolated intact ion pairs in the gas phase compared to effusive sources.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 04, 2011
- Accession Number
- ADA541988
Entities
People
- Amir Golan
- Chen-lin Liu
- Chris Harmon
- Christine J. Koh
- Daniel Strasser
- Ghanshyam L Vaghjiani
- Oleg Kostko
- Stephen R. Leone
- Steven D Chambreau
Organizations
- University of California, Berkeley