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Wiberg (1968) Let's start with the "classic" bond order paper by Ken Wiberg (born in 1927 and still alive!). The Wiberg Bond Index (WBI) between fragments A and B of AB is calculated as follows: \begin{equation} \tag{1} W_{AB} \equiv \sum_{\mu \in A}\sum_{\nu \in B}D_{\mu \nu}^2~ , \end{equation} where $D$ is the following density matrix: \begin{...


9

Actually, if you allow for quasi-2D systems, graphene has had a recent renaissance starting with the experimental discovery of correlated states in "magic angle" twisted bilayer graphene, which was originally predicted by Bistritzer and MacDonald. By stacking two graphene layers with a relative twist, new structures with very long periodicity can ...


9

A possible tool is the ASE python package (open-source): https://wiki.fysik.dtu.dk/ase/ase/cluster/cluster.html Another tool is materials studio software. Unfortunately, it is not free.


8

Nanocut From its site: Nanocut is a program designed to cut out various objects from three dimensional crystal structures. It is aimed to be helpful when creating geometry input for atomistic simulations. Currently it can create following objects: Spherical cluster Polyhedral cluster Cylindrical cluster Spherical wire (1D periodic) Polyhedral wire (1D ...


8

It depends on what you want from it. If you're an organic chemist, you'd be mostly interested in the type of bond (single, double, triple, aromatic), and for that the bond order is most relevant (but tricky to compute). I sent a paper away earlier this year which deals with the choice of bond order analysis, and will post a link to it when it will be online. ...


8

How to test bond order methods for chemical consistency Some of the bond order methods that claim to work do not give consistent results across different SZ values of a spin multiplet or different levels of theory (i.e., basis sets and exchange-correlation functionals). Consequently, there have been several published methods claimed to compute bond orders ...


7

Laplacian Bond Order This method is an extension of the QTAIM (Quantum Theory of Atoms In Molecules) concept of using the Laplacian of the electron density $\nabla^2\rho$ to characterize bonding. Standard QTAIM just uses the value of $\nabla^2\rho$ at bond critical points (minimum electron density along the bond, max along orthogonal directions), but these ...


5

"Has there been any research on the stability of buckminsterfullerene?" There is, for example, this paper with title "Stability of Buckminsterfullerene, C60". It has almost 100 citations. "Has it been proven that buckminsterfullerene is stable?" Stable buckyballs have been made experimentally, and they were also predicted ...


3

How do you model quantum-confinement effects in optically active (e.g. plasmonic) mesoscopic structures? There should be a Comsol module that corresponds to this work, since it's mentioned that they implement the theory using that. Is it possible to use FDTD for simulating mesoscopic structures (nanostructures) where quantum size effects matter? I'm not ...


3

Atomsk I like to use Atomsk to build clusters. Atomsk is a free, Open Source command-line program dedicated to the creation, manipulation, and conversion of data files for atomic-scale simulations. It supports the file formats used by many programs. Atomsk proposes options for applying elementary transformations: duplicate, rotate, deform, insert ...


2

There has indeed been quite a lot of research in this area, as is readily uncovered by searching for "improving the strength of graphene" in your search engine of choice; for example, this 2017 review https://www.sciencedirect.com/science/article/pii/S0079642517300968. Graphene is often highlighted as having high mechanical strength, but this ...


2

In order to visualize structures in VESTA, you need a file with the crystal or molecular structure. This files are very difficult to created by hand. The near structure I found in the ICSD database was for $\ce{Pd_{0.74}Au_{0.08}Si_{0.18}}$. The CIF file is bellow: #(C) 2020 by FIZ Karlsruhe - Leibniz Institute for Information Infrastructure. All rights ...


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