Department of Physics, North Carolina State University, Raleigh, North Carolina 27695-7518, USA.
J Chem Phys. 2010 Jun 7;132(21):214701. doi: 10.1063/1.3427248.
Low temperature scanning tunneling microscopy and spectroscopy have been used to resolve modifications to the Ag(111) surface electronic structure due to the weak adsorption of the nucleobase adenine. Differential conductance spectroscopy recorded at 15 K reveals an upward energetic shift of the surface state native to Ag(111) from a band edge of -67 meV on the clean surface to +82.5 meV recorded over adenine islands. Differential conductance images show the impact of adenine domains on the density of available states as a function of energy relative to the uncovered Ag terraces as well as free-electron-like scattering in the adenine domains. Dispersion of the parallel wave vector of scattered electrons in the adenine domains is compared with the dispersion for electron scattering in bare silver and the ratio of effective masses for electrons in those bands is 1.1+/-0.2. It is hypothesized that this shift occurs due to a combination of effects brought on by the adsorption of adenine including dielectric screening of the first image potential.
低温扫描隧道显微镜和光谱学被用来解析由于弱吸附核苷碱基腺嘌呤导致的 Ag(111)表面电子结构的修饰。在 15 K 下记录的微分电导光谱显示，与清洁表面上的-67 meV 相比，源自 Ag(111)的表面态的能量向上移动了+82.5 meV，这是在腺嘌呤岛上记录的。微分电导图像显示了腺嘌呤域对相对于未覆盖的 Ag 梯田的能量的可用态密度的影响，以及腺嘌呤域中的自由电子散射。在腺嘌呤域中散射电子的平行波矢的色散与裸银中电子散射的色散进行了比较，并且这些能带中电子的有效质量比为 1.1+/-0.2。假设这种位移是由于腺嘌呤的吸附带来的一系列效应引起的，包括第一像极子的介电屏蔽。
