quantum-espresso/PHonon/Doc/INPUT_DYNMAT.def

input_description -distribution {Quantum Espresso} -package PWscf -program dynmat.x {

    toc {}

    intro {
	@b {Purpose of dynmat.x:}

	- reads a dynamical matrix file produced by the phonon code

	- adds the non-analytical part (if Z* and epsilon are read from
          file), applies the chosen Acoustic Sum Rule (if q=0)
	
	- diagonalise the dynamical matrix
	
	- calculates IR and Raman cross sections (if Z* and Raman
	  tensors are read from file, respectively)
	  
	- writes the results to files, both for inspection and for
          plotting

	
        @b {Structure of the input data:}
	========================================================================

        @b &INPUT
	   ...specs of namelist variables...
	@b /
    }
    
    namelist INPUT {

	var fildyn -type CHARACTER {
	    info {
		input file containing the dynamical matrix
	    }
	    default { 'matdyn' }
	}

	dimension q -start 1 -end 3 -type REAL {
	    info {
		calculate LO modes (add non-analytic terms) along the direction q (Cartesian axis)
	    }
	    default { q = (0,0,0) }
	}

	dimension amass -start 1 -end ntyp -type REAL {
	    info {
		mass for each atom type
	    }
	    default { amass is read from file @ref fildyn }
	}

	var  asr -type  CHARACTER {
	    default { 'no' }
            options {
                info {
                    Indicates the type of Acoustic Sum Rule imposed.

                    Allowed values:
                }
                opt -val 'no' {
                    no Acoustic Sum Rules imposed @b (default)
                }               
                opt -val 'simple' {
                    previous implementation of the asr used
                    (3 translational asr imposed by correction of
                     the diagonal elements of the dynamical matrix)
                }               
                opt -val 'crystal' {
                    3 translational asr imposed by optimized
                    correction of the dyn. matrix (projection)
                }                            
                opt -val 'one-dim' {
                    3 translational asr + 1 rotational asr imposed
                    by optimized correction of the dyn. mat. (the
                    rotation axis is the direction of periodicity; it
                    will work only if this axis considered is one of
                    the Cartesian axis).
                }         
                opt -val 'zero-dim' {
                    3 translational asr + 3 rotational asr imposed
                    by optimized correction of the dyn. mat.
                }

                info {
                    Note that in certain cases, not all the rotational asr
                    can be applied (e.g. if there are only 2 atoms in a
                    molecule or if all the atoms are aligned, etc.).  In
                    these cases the supplementary asr are canceled during
                    the orthonormalization procedure (see below).

                    Finally, in all cases except @b 'no' a simple correction
                    on the effective charges is performed (same as in the
                    previous implementation).
                }
            }
        }       
                
        var axis -type INTEGER {
            info {
                indicates the rotation axis for a 1D system (1=Ox, 2=Oy, 3=Oz)
            }
            default { 3 }
        }
        
        var lperm -type LOGICAL {
            info {
                if .true. then calculate Gamma-point mode contributions to
                dielectric permittivity tensor
            }
            default { .false. }
        }

        var lplasma -type LOGICAL {
            info {
                if .true. then calculate Gamma-point mode effective plasma 
                frequencies, automatically triggers @ref lperm = .true.
            }
            default { .false. }
        }

        var filout -type CHARACTER {
            info {
                output file containing phonon frequencies and normalized
                phonon displacements (i.e. eigenvectors divided by the
                square root of the mass and then normalized; they are
                not orthogonal)
            }
            default { 'dynmat.out' }
        }
                
        var fileig -type CHARACTER {
            info {
                output file containing phonon frequencies and eigenvectors
                of the dynamical matrix (they are orthogonal)
            }
            default { ' ' }
        }
        var filmol -type CHARACTER {
            info {
                as above, in a format suitable for molden
            }
            default { 'dynmat.mold' }
        }
        var filxsf -type CHARACTER {
            info {
                as above, in axsf format suitable for xcrysden
            }   
            default { 'dynmat.axsf' }
        }
        var loto_2d -type LOGICAL {
            info {
                set to .true. to activate two-dimensional treatment of LO-TO splitting.
            }   
            default { '.false.' }
        }
        var el_ph_nsig -type INTEGER {
            info {
                The number of double-delta smearing values used in an electron-phonon
                coupling calculation.
            }
        }
        var el_ph_sigma -type REAL {
            info {
                The spacing of double-delta smearing values used in an electron-phonon
                coupling calculation.
            }
        }
    }
}