Electron-Driven Acid-Base Chemistry: Proton Transfer from Hydrogen Chloride to Ammonia
Soren N. Eustis,1
Dunja Radisic,1
Kit H. Bowen,1*
Rafa
A. Bachorz,2,3
Maciej Haranczyk,3,4
Gregory K. Schenter,3
Maciej Gutowski3,4,5*
In contrast to widely familiar acid-base behavior in solution, single molecules of NH3 and HCl do not react to form the ionic salt, NH+4Cl–, in isolation. We applied anion photoelectron spectroscopy and ab initio theory to investigate the interaction of an excess electron with the hydrogen-bonded complex NH3···HCl. Our results show that an excess electron induces this complex to form the ionic salt. We propose a mechanism that proceeds through a dipole-bound state to form the negative ion of ionic ammonium chloride, a species that can also be characterized as a deformed Rydberg radical, NH4, polarized by a chloride anion, Cl–.
1 Department of Chemistry, Johns Hopkins University, Baltimore, MD 21218, USA.
2 Center for Functional Nanostructures (CFN) and Institute of Physical Chemistry, Universität Karlsruhe (TH), D-76128 Karlsruhe, Germany.
3 Chemical and Materials Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA.
4 Department of Chemistry, University of Gda
sk, 80-952 Gdask, Poland.
5 Department of Chemistry, Heriot-Watt University, EH14 4AS Edinburgh, UK.
* To whom correspondence should be addressed. E-mail: kbowen{at}jhu.edu (K.H.B.); m.gutowski{at}hw.ac.uk (M.G.)
