Example data Files

A basin-hopping run of 10,000 MC steps at reduced temperature $ 0.8$ for the Lennard-Jones potential with a constant temperature specified by the `1.0' on the STEPS line. Seeding occurs for the first 100 steps, so a file seed is required in the working directory. The final quenches to produce the output in lowest are much tighter than the relatively `sloppy' quenches for the basin-hopping run (compare the SLOPPYCONV line with the TIGHTCONV line). The maximum number of iterations per conjugate gradient step is 250 for the sloppy quenches and 500 for the tight quenches. The initial linear and angular step parameters are 0.36 and 0.4, and these are adjusted every 50 steps to try and achieve an acceptance ratio of 0.5.


SLOPPYCONV 0.01
TIGHTCONV 1.0D-3
SORT  
MAXIT 250 500
STEPS 10000 1.0
STEP 0.36 0.4
TEMPERATURE 0.8


The next example is similar to the above but employs parameters that seem to be suitable for a Morse potential with $ \rho=6$.


SLOPPYCONV 0.01
TIGHTCONV 1.0D-3
SORT  
EDIFF 0.01
MORSE 6.0
MAXIT 200 500
STEPS 10000 1.0
STEP 0.35 0.4
TEMPERATURE 0.6


Global optimisation for a water cluster using the TIP4P potential. The initial step sizes for translational and orientational rigid-body coordinates are 0.6 and 0.9, respectively, and the block size for separate translational and orientational steps is 200.


SLOPPYCONV 0.01
TIGHTCONV 0.0001
TIP 4
CENTRE  
MAXIT 1000 1000
STEPS 50000 1.0
STEP 0.6 0.0 0.9 200
TEMPERATURE 5.0


The following input file specifies a basin-sampling run to calculate the density of states for a LJ$ _{13}$ cluster. The system is confined to a spherical container of radius $ 1.8\,\sigma$, the geometry will be perturbed by $ 0.2\,\sigma$ at each step with no angular steps allowed. The run will terminate after $ 1000000$ MC steps or when the WL convergence criterion targetwl is satisfied, whichever is the earliest. Setting the temperature to zero indicates that a Wang-Landau type MC is used instead of a conventional temperature-dependent MC run. In keyword HISTOGRAM the energy of the global minimum of LJ$ _{13}$ $ -44.3268\,\epsilon$ is chosen as the energy of the lowest bin histmin, the energy spectrum above that point is separated into $ 50$ bins of width $ 0.25$ each. The starting modification factor and target number of WL iterations are histfac =$ 1.01$ and targetwl =$ 10$. A square root function will be used for decreasing the modification factor upon completion of each WL iteration, and the convergence schedule is regulated by VISITPROP.


SLOPPYCONV 0.001
TIGHTCONV 1.0D-3
MAXBFGS 0.1
EDIFF 0.003
RADIUS 1.8
MAXIT 1000 500
STEPS 1000000 1.0
STEP 0.2 0.0
TEMPERATURE 0.0
HISTOGRAM -44.3268014195 $ \:$ 0.2 $ \:$ 1.1D0 $ \:$ 50 $ \:$ 0.5 $ \:$ 10 $ \:$ 0.2
EQUILIBRATION 1 100  
FIXBOTH  
BINSTRUCTURES 1  
VISITPROP  


The following input specifies a local geometry relaxation for a metal (001) surface modelled by the Sutton-Chen potential, smoothly truncated at 2.5Å. The model parameters are for Ag, and the expected input coordinates are a $ [0,5a_{0}] \times [0,5a_{0}] \times [0,X]$ face-centred-cubic slab with the lattice parameter $ a_{0} = 1.0$Å and $ X < 90$Å. Periodic boundary conditions are imposed in all three dimensions, but the box length in the $ z$ direction is made large to create vacuum. The bottom two layers ($ z = 0.0$ and $ z=0.5$) containing 100 atoms are frozen to mimic an infinite half-space.


TIGHTCONV 1.0D-4
SLOPPYCONV 1.0D-3
MSC 1 12 6 1.0 1.0 144.41
CUTOFF 2.5
PERIODIC 5.0 5.0 100.0
MAXIT 500 500
STEPS 0 1.0
STEP 0.0 0.0
FREEZE 1 2 3 4 5 6 7 8 9 10
FREEZE 11 12 13 14 15 16 17 18 19 20
FREEZE 21 22 23 24 25 26 27 28 29 30
FREEZE 31 32 33 34 35 36 37 38 39 40
FREEZE 41 42 43 44 45 46 47 48 49 50
FREEZE 51 52 53 54 55 56 57 58 59 60
FREEZE 61 62 63 64 65 66 67 68 69 70
FREEZE 71 72 73 74 75 76 77 78 79 80
FREEZE 81 82 83 84 85 86 87 88 89 90
FREEZE 91 92 93 94 95 96 97 98 99 100


David Wales 2017-09-20