Fan Dingxin, Sakai Yuki, Chelikowsky James R
Nano Lett. 2019 Aug 14;19(8):5562-5567. doi: 10.1021/acs.nanolett.9b02097. Epub 2019 Aug 6.
Noncontact atomic force microscopy (nc-AFM) with a CO-functionalized tip can image submolecular structures through high-resolution images with the possibility of discriminating bond order. We employ real-space pseudopotential calculations to simulate nc-AFM images of molecules containing double (dibenzo(cd,n)naphtho(3,2,1,8-pqra)perylene (DBNP), hexabenzo(bc,ef,hi,kl,no,qr)coronene (HBC)) and triple (1,2-bis[2-(2-ethynylphenyl)ethynyl]-benzene (BEEB), 6-phenylhexa-1,3,5-triynylbenzene (PHTB)) bonds. We find (1) triple bonds can be unambiguously distinguished from other interatomic interactions based on a characteristic image and (2) the degree of double bond character can be directly determined from the image. We propose that large lateral forces acting on the tip may induce specific image distortions in the cases of DBNP and BEEB.
具有 CO 功能化探针的非接触式原子力显微镜（nc-AFM）能够通过高分辨率图像对亚分子结构进行成像，并且有可能区分键序。我们采用实空间赝势计算来模拟含有双键（二苯并（cd，n）萘并（3，2，1，8-pqra）苝（DBNP）、六苯并（bc，ef，hi，kl，no，qr）蒄（HBC））和三键（1，2-双[2-（2-乙炔基苯基）乙炔基]-苯（BEEB）、6-苯基六-1，3，5-三炔基苯（PHTB））的分子的 nc-AFM 图像。我们发现：（1）基于特征图像，三键能够与其他原子间相互作用明确区分开来；（2）双键特征程度可直接从图像中确定。我们提出，在 DBNP 和 BEEB 的情况下，作用于探针的大横向力可能会导致特定的图像畸变。
