Zero electron kinetic energy spectroscopy of the ArCl- anion

Zero electron kinetic energy (ZEKE) spectroscopy has been utilized to study the (ArCl-)-Ar-40-Cl-35 anion and the X1/2, I3/2 and II1/2 electronic stat es of neutral ArCl. Well-resolved progressions in the low-frequency vibrati ons of the anion and the neutral complexes are observed in the ZEKE spectra . From our spectroscopic data we construct model potential functions for th e anion and three neutral states. This yields refined values for the neutra l state splittings and the first accurate experimental ArCl- anion potentia l. Absolute uncertainties for R-m and epsilon in all potentials are estimat ed to be +/-0.08 Angstrom and +/-0.6 meV, respectively. (C) 1999 American I nstitute of Physics. [S0021-9606(99)01819-X].