A Novel Delaunay Simplex Technique for Detection of Crystalline Nuclei in Dense Packings of Spheres

Author(s):  
A. V. Anikeenko ◽  
M. L. Gavrilova ◽  
N. N. Medvedev
1997 ◽  
Vol 7 (2) ◽  
pp. 247-254 ◽  
Author(s):  
N. N. Sinelnikov ◽  
M. A. Mazo ◽  
Al. Al. Berlin
Keyword(s):  

2014 ◽  
Vol 89 (4) ◽  
Author(s):  
A. Mughal ◽  
D. Weaire
Keyword(s):  

2018 ◽  
Vol 4 (6) ◽  
Author(s):  
Thibaud Maimbourg ◽  
Mauro Sellitto ◽  
Guilhem Semerjian ◽  
Francesco Zamponi

Packing spheres efficiently in large dimension dd is a particularly difficult optimization problem. In this paper we add an isotropic interaction potential to the pure hard-core repulsion, and show that one can tune it in order to maximize a lower bound on the packing density. Our results suggest that exponentially many (in the number of particles) distinct disordered sphere packings can be efficiently constructed by this method, up to a packing fraction close to 7 \, d \, 2^{-d}7d2−d. The latter is determined by solving the inverse problem of maximizing the dynamical glass transition over the space of the interaction potentials. Our method crucially exploits a recent exact formulation of the thermodynamics and the dynamics of simple liquids in infinite dimension.


10.37236/1223 ◽  
1994 ◽  
Vol 2 (1) ◽  
Author(s):  
R. L. Graham ◽  
B. D. Lubachevsky

Previously published packings of equal disks in an equilateral triangle have dealt with up to 21 disks. We use a new discrete-event simulation algorithm to produce packings for up to 34 disks. For each $n$ in the range $22 \le n \le 34$ we present what we believe to be the densest possible packing of $n$ equal disks in an equilateral triangle. For these $n$ we also list the second, often the third and sometimes the fourth best packings among those that we found. In each case, the structure of the packing implies that the minimum distance $d(n)$ between disk centers is the root of polynomial $P_n$ with integer coefficients. In most cases we do not explicitly compute $P_n$ but in all cases we do compute and report $d(n)$ to 15 significant decimal digits. Disk packings in equilateral triangles differ from those in squares or circles in that for triangles there are an infinite number of values of $n$ for which the exact value of $d(n)$ is known, namely, when $n$ is of the form $\Delta (k) := \frac{k(k+1)}{2}$. It has also been conjectured that $d(n-1) = d(n)$ in this case. Based on our computations, we present conjectured optimal packings for seven other infinite classes of $n$, namely \begin{align*} n & = & \Delta (2k) +1, \Delta (2k+1) +1, \Delta (k+2) -2 , \Delta (2k+3) -3, \\ && \Delta (3k+1)+2 , 4 \Delta (k), \text{ and } 2 \Delta (k+1) + 2 \Delta (k) -1 . \end{align*} We also report the best packings we found for other values of $n$ in these forms which are larger than 34, namely, $n=37$, 40, 42, 43, 46, 49, 56, 57, 60, 63, 67, 71, 79, 84, 92, 93, 106, 112, 121, and 254, and also for $n=58$, 95, 108, 175, 255, 256, 258, and 260. We say that an infinite class of packings of $n$ disks, $n=n(1), n(2),...n(k),...$, is tight , if [$1/d(n(k)+1) - 1/d(n(k))$] is bounded away from zero as $k$ goes to infinity. We conjecture that some of our infinite classes are tight, others are not tight, and that there are infinitely many tight classes.


2021 ◽  
Vol 13 (2) ◽  
pp. 157-168
Author(s):  
Nikolay K. Balabaev ◽  
◽  
Galina M. Agayan ◽  
Margarita N. Rodnikova ◽  
Irina A. Solonina ◽  
...  

The mixed network of hydrogen bonds in the ethylene glycol (EG) - monoethanolamine (MEA) system is described by molecular dynamics (MD) methods, graph theory, and Delaunay simplexes at 300 K in the entire concentration range. It is shown that at low MEA concentrations, all molecules in the system are linked into a spatial network of H-bonds; at high MEA concentrations, this number is 96%. Detailed characteristics of the networks are given. The resulting picture is expanded by studying the system using the Delaunay simplex method. The calculations are compared for different charges on the atoms of the MEA molecule.


2006 ◽  
Vol 36 (3a) ◽  
Author(s):  
H. J. Herrmann ◽  
R. Mahmoodi Baram ◽  
M. Wackenhut
Keyword(s):  

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