We present the mass spectral and photoelectron spectroscopic results of our study of (HF)(2)(-). Our main findings are as follows. The (HF)(2)(-) anion was observed experimentally for the first time, confirming the 20 year old prediction of Jordan and Wendoloski. The photoelectron spectrum of (HF)(2)(-) exhibits a distinctive spectral signature, which we have come to recognize as being characteristic of dipole bound anions. The vertical detachment energy (VDE) of (HF)(2)(-) has been determined to be 63+/-3 meV, and the adiabatic electron affinity (EA(a)) of (HF)(2) was judged to be close to this value as well. Relatively weak spectral features, characteristic of intramolecular vibrations in the final (neutral dimer) state, were also observed. We have interpreted these results in terms of slight distortions of the dimer anion's geometric structure which lead to an enhanced dipole moment. This interpretation is supported to a considerable extent by theoretical calculations reported in the companion paper by Gutowski and Skurski. (C) 1997 American Institute of Physics.