Note: These key words must be present in the phonons_input.dat file, or PhonTS will terminate with the error!
species
| Format: | species N C(2) R1 R2 … |
| Description: | This keyword determines the number (N) and type of different species present in your system. N following lines (one per species) each need to contain three entries: name of the specie (C(2)), atomic mass (R1) and charge (R2). |
| Examples: | species 1 Ar 40.0 0.00 species 2 U 238.20 2.70 O 16.00 -1.35 |
lattice
| Format: | Lattice R |
| Description: | Lattice constant of the supplied structure. This quantity really defines a length scale which will be used in the cell definition. |
| Examples: | lattice 5.4 |
cell
| Format: | cell R1 R2 R3 |
| Description: | Specifies the dimensions of the simulation cell in the units of the lattice constant. Through this keyword, PhonTS supports only orthorhombic cells (α=β=γ=90o), thus it requires 3 real numbers corresponding to x,y and z dimensions of the cell. If other cell types are required, please use “vectors” keyword instead. |
| Examples: | cell 1.0 1.0 1.0 |
vectors
| Format: | vectors R1 R2 R3 R4 R5 R6 R7 R8 R9 |
| Description: | Specifies the lattice vectors in the units of the lattice constant. It requires 3 vectors to be specified, 3 real numbers each, that correspond to x,y and z components. Only one of “cell” or “vectors” keywords need to be specfied. |
| Examples: | vectors 0.5 0.5 0.0 0.5 0.0 0.5 0.0 0.5 0.5 |
natoms
| Format: | natoms N |
| Description: | Number of atoms in the supplied cell. |
| Examples: | natoms 4 |
fractional
| Format: | fractional C(2) R1 R2 R3 … |
| Description: | Specifies that the list of atoms in the cell (which has to follow this keyword) will be in the fractional coordinates with respect to the cell size. The list of atoms is organized as follows: one atom per line, each contain the species name, followed by x,y and z coordinates. |
| Examples: | fractional U 0.00 0.00 0.00 U 0.00 0.50 0.50 U 0.50 0.00 0.50 U 0.50 0.50 0.00 O 0.25 0.25 0.25 O 0.75 0.25 0.25 O 0.75 0.75 0.25 O 0.25 0.75 0.25 O 0.25 0.25 0.75 O 0.75 0.25 0.75 O 0.75 0.75 0.75 O 0.25 0.75 0.75 |
cartesian
| Format: | cartesian C(2) R1 R2 R3 … |
| Description: | Specifies that the list of atoms in the cell (which has to follow this keyword) will be in the absolute cartesian coordinates. The list of atoms is organized as follows: one atom per line, each contain the species name followed by x,y and z coordinates. Note: only one of fractional or cartesian need to be specified. |
| Examples: | cartesian Ar 0.00 0.00 0.00 Ar 0.00 2.70 2.70 Ar 2.70 0.00 2.70 Ar 2.70 2.70 0.00 |
end
| Format: | end |
| Description: | This keyword signifies the end of the input file; everything after that keyword will be ignored. |
| Examples: | end |