  Imaging the charge distributions and structures of molecules and clusters
will promote the understanding of the dynamics of the quantum system. Here, we
report a method by using an Ar atom as a tip to probe the charge distributions
of benzene (Bz) cations in gas phase. Remarkably, the measured charge
distributions of Bz cation (QH =0.204,QC=-0.037)and dication (QH
=0.248,QC=0.0853)agree well with the calculated Mulliken distributions,and the
structures of Bz dimer is reconstructed by using the measured charge
distributions. The structures of two Bz dimer isomers (T-shaped and PD isomers)
can be resolved from the measured inter-molecular potential V(R) between two Bz
ions, and the structures of Bz dimer agree well with the theoretical
predictions.
