TiAl structure optimisation

TODO Write some text motivating this example

Setup system:

using AtomsIO
using EmpiricalPotentials

system = load_system(joinpath(pkgdir(EmpiricalPotentials), "data/TiAl-1024.xyz"))

Setup calculator:

using Unitful
using UnitfulAtomic

# Note: These are completely made up parameters,
#       please do not use in production
rcut = 5.0u"Å"
zAl = atomic_number(ChemicalSpecies(:Al))
zTi = atomic_number(ChemicalSpecies(:Ti))
emins = Dict( (zAl, zAl) => -1.0u"eV",
              (zAl, zTi) => -1.234u"eV",
              (zTi, zTi) => -0.345u"eV" )
rmins = Dict( (zAl, zAl) => 2.7u"Å",
              (zAl, zTi) => 3.2u"Å",
              (zTi, zTi) => 3.0u"Å" )
calc = LennardJones(emins, rmins, rcut)

Minimise energy:

using GeometryOptimization

results = minimize_energy!(system, calc, OptimCG(); maxiters=10, verbosity=1)
Geometry optimisation convergence (in atomic units)
┌─────┬─────────────────┬───────────┬─────────────┬────────┐
│   n │          Energy │ log10(ΔE) │  max(Force) │  Δtime │
├─────┼─────────────────┼───────────┼─────────────┼────────┤
│   0 │ +1096.106742193 │           │     93.6673 │  2.37s │
│   1 │ +759.2146774682 │           │     38.9777 │  167ms │
│   2 │ +622.1968295849 │      2.14 │     10.8691 │  149ms │
│   3 │ +512.9274471938 │      2.04 │     3.35485 │  179ms │
│   4 │ +403.9790783927 │      2.04 │     3.27035 │  426ms │
│   5 │ +337.0567526540 │      1.83 │     1.29657 │  120ms │
│   6 │ +289.9055274614 │      1.67 │     2.22107 │  135ms │
│   7 │ +251.8014072359 │      1.58 │      1.1998 │  138ms │
│   8 │ +224.7319048925 │      1.43 │     1.15443 │  130ms │
│   9 │ +203.7017649518 │      1.32 │    0.749834 │  117ms │
│  10 │ +189.1882801930 │      1.16 │    0.647875 │  125ms │
┌ Warning: Geometry optimisation not converged.
@ GeometryOptimization ~/work/GeometryOptimization.jl/GeometryOptimization.jl/src/minimize_energy.jl:184

Final structure:

results.system
FlexibleSystem(Al₅₁₂Ti₅₁₂, periodicity = TTT):
    cell_vectors      : [ 21.6648        0        0;
                                0  21.6648        0;
                                0        0  31.2377]u"Å"
    energy            : -108891.754076
    config_type       : TiAl_T5000