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 |
| CENTRE | |
| 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 ρ = 6.
| SLOPPYCONV | 0.01 |
| TIGHTCONV | 1.0D-3 |
| CENTRE | |
| 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 LJ13 cluster. The system is confined to a spherical container of radius 1.8 σ, the geometry will be perturbed by 0.2 σ 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 LJ13 -44.3268 ε 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, 5a0]×[0, 5a0]×[0, X] face-centred-cubic slab with the lattice parameter a0 = 1.0Å and X < 90Å. 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 |