How do you define a region in LAMMPS?
Regions in LAMMPS do not get wrapped across periodic boundaries, as specified by the boundary command. For example, a spherical region that is defined so that it overlaps a periodic boundary is not treated as 2 half-spheres, one on either side of the simulation box.
How do you make lattice in LAMMPS?
A lattice is used by LAMMPS in two ways. First, the create_atoms command creates atoms on the lattice points inside the simulation box. Note that the create_atoms command allows different atom types to be assigned to different basis atoms of the lattice.
What is lattice in Lammps?
In LAMMPS, a lattice is simply a set of points in space, determined by a unit cell with basis atoms, that is replicated infinitely in all dimensions. The arguments of the lattice command can be used to define a wide variety of crystallographic lattices.
What lattice constants define a unit cell?
The lattice parameters are the quantities specifying a unit cell or the unit of the periodicity of the atomic arrangement. The lattice parameters (constants) are composed of “a, b, c,” lengths of the unit cell in three dimensions, and “α, β, γ,” their mutual angles.
Which unit cell has three lattice parameters?
The triclinic lattice is chosen such that all the internal angles are either acute or obtuse. This crystal system has the lowest symmetry and must be described by 3 lattice parameters (a, b, and c) and the 3 angles (α, β, and γ).
What is SC BCC and FCC?
STRUCTURE (SC) BODY CENTERED. CUBIC STRUCTURE (BCC) FACE CENTERED. CUBIC STRUCTURE (FCC)
What is lattice parameter of BCC?
In BCC iron, carbon atoms enter tetrahedral sites, such as 1/4, 1/2, 0. The lattice parameter is 0.3571 nm for FCC iron and 0.2866 nm for BCC iron.
What is APF of FCC?
• APF = 0.74. Face-Centered Cubic (FCC) Structure. • Unit cell contains: 6 x 1/2 + 8 x 1/8 = 4 atoms/unit cell. • Coordination number = 12.
How is APF calculated in SC?
Simply take the length of the line covered by circles, and divide by the total length of the line. The maximum packing factor is 1, which means 100% of the line is occupied by a circle.
What is LAMMPS?
LAMMPS is a classical molecular dynamics code with a focus on materials modeling. It’s an acronym for Large-scale Atomic/Molecular Massively Parallel Simulator. LAMMPS has potentials for solid-state materials (metals, semiconductors) and soft matter (biomolecules, polymers) and coarse-grained or mesoscopic systems.
What is a spherical region in LAMMPS?
For example, a spherical region that is defined so that it overlaps a periodic boundary is not treated as 2 half-spheres, one on either side of the simulation box. Regions in LAMMPS are always 3d geometric objects, regardless of whether the dimension of a simulation is 2d or 3d.
What is a dynamic region in LAMMPS?
Normally, regions in LAMMPS are “static”, meaning their geometric extent does not change with time. If the move or rotate keyword is used, as described below, the region becomes “dynamic”, meaning it’s location or orientation changes with time.
What is LAMMPS 2021?
2021 Virtual LAMMPS Workshop and Symposium, Aug 10-13, hosted by Temple University. LAMMPS is a classical molecular dynamics code with a focus on materials modeling.