Prof. Philip Moriarty from the University of Nottingham will give a seminar on Wednesday the 20th of April, at 1 pm (room ENG209 in the Engineering Hub, building 13 on the university map). Please join us in attending this very interesting talk on dynamic force microscopy and Pauli’s principle.
Do we really see chemical bonds?
Exceptionally clear images of intra-molecular structure can now be attained in dynamic force microscopy (DFM) through the combination of tip-apex control and operation in what has become known as the “Pauli exclusion regime” of the tip-sample interaction [1-4]. (See, for example, the figure below, taken from Ref. 4, which shows a DFM image of a 2D assembly of NTCDI molecules alongside a ball-and-stick model of the molecule where blue spheres represent nitrogen atoms, and red spheres are oxygen.)
I will discuss a number of aspects of the exclusion principle which underpin this ability to achieve sub-molecular resolution. My particular focus will be on the interpretation of Pauli’s principle in the context of interatomic and intermolecular interactions, what this means for the quantitative analysis of ultra-high resolution force microscopy data, and whether or not we really see chemical bonds in DFM images [5,6].
 L Gross, F Mohn, N Moll, P Liljeroth, and G Meyer. Science, 325 (2009) 1110
 Dimas G. de Oteyza, et al.,Science, 340 (2013) 1434
 Jun Zhang, Pengcheng Chen, Bingkai Yuan, Wei Ji, Zhihai Cheng, and Xiaohui Qiu, Science 342 (2013) 611
 A Sweetman, SP Jarvis, H Sang, I Lekkas, P Rahe, Y Wang, J Wang, N Champness, L Kantorovich, and P Moriarty, Nature Comm. 5 (2014) 3931
 P Hapala, G Kichin, CF Wagner, S Tautz, R Temirov, and P Jelinek, Phys Rev B 90, 085421 (2014); Sampsa K. Hämäläinen, Nadine van der Heijden, Joost van der Lit, Stephan den Hartog, Peter Liljeroth, and Ingmar Swart, Phys. Rev. Lett. 113, 186102 (2014)
 S. P. Jarvis, M. A. Rashid, A. Sweetman, J. Leaf, S. Taylor, P. Moriarty, and J. Dunn
Phys. Rev. B 92, 241405(R) (2015)