Measuring Charge Distribution of Molecular Cations by an Atomic Coulomb Probe Microscope

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⁺(δ_H=0.204,δ_C=-0.037) and Bz²⁺(δ_H=0.248,δ_C=0.0853) agree well with the calculated Mulliken distributions,and the struc...     

Ultrafast Coulomb explosion imaging of molecules and molecular clusters

Taking an image of their structure and a movie of their dynamics of small quantum systems have always been a dream of physicists and chemists. Laser-induced Coulomb explosion imaging (CEI) provides a great opportunity to make this dream a reality for small molecules or their aggregation —— clusters. The method is unique for identifying the atomic locations with ångstrom spatial resolution and capturing the structural evolution with a femtosecond time scale, in particular for imaging transient state products. This review summarizes the determination of three-dimensional equilibrium geometry of molecules and molecular cluster system through the reconstruction from the fragments momenta, and also shows that the dissociation dynamics on the complex potential energy surface can be tracked in real-time with the ultrafast CEI (UCEI). Furthermore, the detailed measurement and analysis procedures of the CEI, theoretical methods, exemplary results, and future perspectives of the technique are described.