Open AccessTHEORETICAL SIMULATIONS OF STM IMAGES FOR C60 WITH DIFFERENT ADSORBED ORIENTATIONS
Author(s) -
Qunxiang Li,
Jiali Yang,
J. G. Hou,
Kelin Wang,
Qingshi Zhu
Publication year - 1999
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.48.1477
Subject(s) - scanning tunneling microscope , adsorption , materials science , charge density , homo/lumo , orientation (vector space) , density functional theory , charge (physics) , surface (topology) , molecule , substrate (aquarium) , molecular dynamics , chemical physics , molecular physics , physics , nanotechnology , chemistry , computational chemistry , geometry , quantum mechanics , mathematics , oceanography , geology
The highest occupied molecular orbitle(HOMO) and lowest unoccupied molecular orbitle(LUMO) charge density distributions of adsorbed C60 with different orientations are calculated by using discreted variational-local density functional (DV-LDF) method. The theoretical simulations of scanning tunneling microscope (STM) images are based on Tersoff-Hamann theory. The results show that the charge density distribution parttens have their own‘fingerprint’. The LUMO charge distributions are more reliable than HOMO distributions when using them to simulate STM images. The molecular orientations can be easily determined by comparing with observed STM images in experiments and theoretical calculations in the literatures. Morevoer, according to the STM images obtained from our experiments, a new adsorbed orientation of C60 on Si(111)-7×7 surface has been found. Namely, C60 can adsorb with its 5—6 bond facing towards the substrate surface. At the same time, experimentalist can get some useful imformation from the results of this paper, and the orientations of the other molecules can also be determined by using the method.