@article{bff4ca9b6fa843bf93f118192f74b515,
title = "Observation of electron orbital signatures of single atoms within metal-phthalocyanines using atomic force microscopy",
abstract = "Resolving the electronic structure of a single atom within a molecule is of fundamental importance for understanding and predicting chemical and physical properties of functional molecules such as molecular catalysts. However, the observation of the orbital signature of an individual atom is challenging. We report here the direct identification of two adjacent transition-metal atoms, Fe and Co, within phthalocyanine molecules using high-resolution noncontact atomic force microscopy (HR-AFM). HR-AFM imaging reveals that the Co atom is brighter and presents four distinct lobes on the horizontal plane whereas the Fe atom displays a “square” morphology. Pico-force spectroscopy measurements show a larger repulsion force of about 5 pN on the tip exerted by Co in comparison to Fe. Our combined experimental and theoretical results demonstrate that both the distinguishable features in AFM images and the variation in the measured forces arise from Co{\textquoteright}s higher electron orbital occupation above the molecular plane. The ability to directly observe orbital signatures using HR-AFM should provide a promising approach to characterizing the electronic structure of an individual atom in a molecular species and to understand mechanisms of certain chemical reactions.",
author = "Pengcheng Chen and Dingxin Fan and Annabella Selloni and Carter, {Emily A.} and Arnold, {Craig B.} and Yunlong Zhang and Gross, {Adam S.} and Chelikowsky, {James R.} and Nan Yao",
note = "Funding Information: This work was partially supported by ExxonMobil through its membership in the Princeton E-ffiliates Partnership of the Andlinger Center for Energy and the Environment. P.C., D.F., and N.Y. acknowledge partial support from the Innovation Award from J. Insley Blair-Pyne Fund and the Evin-Catalysis Initiative Award at Princeton. This research made use of the Imaging and Analysis Center operated by the Princeton Materials Institute at Princeton University, which is supported in part by the Princeton Center for Complex Materials, a National Science Foundation Materials Research Science and Engineering Center (Grant No. DMR-2011750). D.F. and J.R.C. acknowledge support from the Welch Foundation under grant F-2094. The National Energy Research Scientific Computing (NERSC) and the Texas Advanced Computing Center (TACC) provided computational resources. Funding Information: This work was partially supported by ExxonMobil through its membership in the Princeton E-ffiliates Partnership of the Andlinger Center for Energy and the Environment. P.C., D.F., and N.Y. acknowledge partial support from the Innovation Award from J. Insley Blair-Pyne Fund and the Evin-Catalysis Initiative Award at Princeton. This research made use of the Imaging and Analysis Center operated by the Princeton Materials Institute at Princeton University, which is supported in part by the Princeton Center for Complex Materials, a National Science Foundation Materials Research Science and Engineering Center (Grant No. DMR-2011750). D.F. and J.R.C. acknowledge support from the Welch Foundation under grant F-2094. The National Energy Research Scientific Computing (NERSC) and the Texas Advanced Computing Center (TACC) provided computational resources. Publisher Copyright: {\textcopyright} 2023, The Author(s).",
year = "2023",
month = dec,
doi = "10.1038/s41467-023-37023-9",
language = "English (US)",
volume = "14",
journal = "Nature communications",
issn = "2041-1723",
publisher = "Nature Publishing Group",
number = "1",
}