Analysis of surface electronic structure by STM with resonance excitation

（1）STM同步测量装置的研制。研制了扫描探针显微镜STM、STS和STM光发射测量实验系统。STM发射的光通过安装在STM头中的透镜收集。通过STM控制器与光学探测系统之间的通信，可以同时进行这三种测量，从而实现STM形貌图像、STS局域态密度和STM诱导光发射光谱的比较。（2）光发射谱与局域态密度的比较我们测量了吸附在Au（111）表面的有机分子在低温（约77K）下STM诱导的光发射。对Au（111）表面的辛二硫醇薄膜进行了STS和STM测量，同时测量了其发射光谱，并将光谱与STM的形貌图像和STS的局域态密度进行了关联。这些数据与清洁Au（111）表面的数据进行了比较。在清洁Au（111）表面的发射峰的长波长侧观察到分子吸附引起的光谱的峰位和光谱形状的变化：这些变化可以用辛二硫醇在Au（111）表面上吸附引起的局域态密度的变化来解释：在费米能级附近态密度降低，在费米能级以上态密度增加。这一比较已成功地进行了第一次的基础上，同时测量我们的实验系统

(1)Development of apparatus for simultaneous measurements of STM. STS and STM light emission spectra.The experimental system of Scanning Probe Microscopy for STM, STS and STM light, emission measurements has been developed. The light emitted from STM is collected by using lens installed in STM head. These three kinds of measurements can be made simultaneously by communicating between STM controller and optical detecting system, which enables us the comparison among topographic image by STM, local density of states by STS and optical spectra by STM-induced light emission.(2)Comparison of light emission spectra with local density of states.We have measured STM-induced light emission from organic molecules adsorbed Au(111) surface at low temperatures of about 77K. The emission spectra have been measured at the same time of STS and STM measurements for octanedithiol films on Au(111) surfaces, and the optical spectra been correlated with topographic images by STM and local density of states by STS. These data have been compared with those for the clean Au(111) surface's.The change of optical spectra due to molecule adsorption has been observed in peak position and spectral shape in the longer wavelength side, of emission peak for' clean Au(111) surface : These change can be explained by the change in local density of states due to octanedithiol adsorption on Au (111) : the decrease in density of states at the energy near Fermi level and the increase above 0.3eV with respect to Fermi level. This comparison has been made successfully for the first time based on the simultaneous measurements by our experimental system