System for imaging and detecting threshold phenomena associated with and/or atomic or molecular spectra of a substance by reflection of an AC electrical signal

摘要

A microwave sweep oscillator is used to apply an AC signal from the probe tip of a scanning tunneling microscope to a sample, and the reflected signal from the sample is measured by a microwave spectrum/network analyzer, or another device capable of measuring amplitude versus frequency. The frequency of the signal applied by the oscillator may be swept across a spectrum and the optimum frequency of the spectrum is determined so that an improved image of the surface of a sample may be obtained. The spectrum of a known substance may also be recorded and used as a signature for identifying components of an unknown substance by comparison. When the amplitude of the AC signal applied is increased, a sudden change in the response indicates a threshold. By reducing the frequency, the response will indicate charge dissipation characteristics of the sample. When applied to electrochemical cells, this invention is particularly useful for measuring dynamic information of the electrochemical cell.