------------------------------------------------------------------------ INPUT FILE DESCRIPTION Program: ph.x / PWscf / Quantum Espresso ------------------------------------------------------------------------ Input data format: { } = optional, [ ] = it depends, # = comment Structure of the input data: =============================================================================== title_line &INPUTPH ... / xq(1) xq(2) xq(3) [ atom(1) atom(2) ... atom(nat_todo) ] # if "nat_todo" was specified ======================================================================== Line of input: title_line DESCRIPTION OF ITEMS: +-------------------------------------------------------------------- Variable: title_line Type: CHARACTER Description: Title of the job, i.e., a line that is reprinted on output. +-------------------------------------------------------------------- ===End of line-of-input================================================= ======================================================================== NAMELIST: &INPUTPH +-------------------------------------------------------------------- Variable: amass(i), i=1,ntyp Type: REAL Default: 0.0 Description: Atomic mass [amu] of each atomic type. If not specified, masses are read from data file. +-------------------------------------------------------------------- +-------------------------------------------------------------------- Variable: outdir Type: CHARACTER Default: value of the ESPRESSO_TMPDIR environment variable if set; current directory ('./') otherwise Description: Directory containing input, output, and scratch files; must be the same as specified in the calculation of the unperturbed system. +-------------------------------------------------------------------- +-------------------------------------------------------------------- Variable: prefix Type: CHARACTER Default: 'pwscf' Description: Prepended to input/output filenames; must be the same used in the calculation of unperturbed system. +-------------------------------------------------------------------- +-------------------------------------------------------------------- Variable: niter_ph Type: INTEGER Default: maxter=100 Description: Maximum number of iterations in a scf step. If you want more than 100, edit variable "maxter" in PH/phcom.f90 +-------------------------------------------------------------------- +-------------------------------------------------------------------- Variable: tr2_ph Type: REAL Default: 1e-12 Description: Threshold for self-consistency. +-------------------------------------------------------------------- +-------------------------------------------------------------------- Variable: alpha_mix(niter) Type: REAL Default: alpha_mix(1)=0.7 Description: Mixing factor (for each iteration) for updating the scf potential: vnew(in) = alpha_mix*vold(out) + (1-alpha_mix)*vold(in) +-------------------------------------------------------------------- +-------------------------------------------------------------------- Variable: nmix_ph Type: INTEGER Default: 4 Description: Number of iterations used in potential mixing. +-------------------------------------------------------------------- +-------------------------------------------------------------------- Variable: iverbosity Type: INTEGER Default: 0 Description: 0 = short output 1 = verbose output +-------------------------------------------------------------------- +-------------------------------------------------------------------- Variable: reduce_io Type: LOGICAL Default: .false. Description: Reduce I/O to the strict minimum. +-------------------------------------------------------------------- +-------------------------------------------------------------------- Variable: max_seconds Type: REAL Default: 1.d7 Description: Maximum allowed run time before the job stops smoothly. +-------------------------------------------------------------------- +-------------------------------------------------------------------- Variable: fildyn Type: CHARACTER Default: 'matdyn' Description: File where the dynamical matrix is written. +-------------------------------------------------------------------- +-------------------------------------------------------------------- Variable: fildrho Type: CHARACTER Default: ' ' Description: File where the charge density responses are written. +-------------------------------------------------------------------- +-------------------------------------------------------------------- Variable: fildvscf Type: CHARACTER Default: ' ' Description: File where the the potential variation is written (for later use in electron-phonon calculation). +-------------------------------------------------------------------- +-------------------------------------------------------------------- Variable: epsil Type: LOGICAL Default: .false. Description: If .true. in a q=0 calculation for a non metal the macroscopic dielectric constant of the system is computed. Do not set epsil to .true. if you have a metallic system or q/=0: the code will complain and stop. +-------------------------------------------------------------------- +-------------------------------------------------------------------- Variable: lrpa Type: LOGICAL Default: .false. Description: If .true. the dielectric constant is calculated at the RPA level with DV_xc=0. +-------------------------------------------------------------------- +-------------------------------------------------------------------- Variable: lnoloc Type: LOGICAL Default: .false. Description: If .true. the dielectric constant is calculated without local fields, i.e. by setting DV_H=0 and DV_xc=0. +-------------------------------------------------------------------- +-------------------------------------------------------------------- Variable: trans Type: LOGICAL Default: .true. Description: If .true. the phonons are computed. If trans .and. epsil are .true. effective charges are calculated. +-------------------------------------------------------------------- +-------------------------------------------------------------------- Variable: lraman Type: LOGICAL Default: .false. Description: If .true. calculate non-resonant Raman coefficients using second-order response as in: M. Lazzeri and F. Mauri, Phys. Rev. Lett. 90, 036401 (2003). +-------------------------------------------------------------------- ///--- OPTIONAL VARIABLES FOR RAMAN: +-------------------------------------------------------------------- Variable: eth_rps Type: REAL Default: 1.0d-9 Description: Threshold for calculation of Pc R |psi>. +-------------------------------------------------------------------- +-------------------------------------------------------------------- Variable: eth_ns Type: REAL Default: 1.0e-12 Description: Threshold for non-scf wavefunction calculation. +-------------------------------------------------------------------- +-------------------------------------------------------------------- Variable: dek Type: REAL Default: 1.0e-3 Description: Delta_xk used for wavefunction derivation wrt k. +-------------------------------------------------------------------- \\\--- +-------------------------------------------------------------------- Variable: recover Type: LOGICAL Default: .false. Description: If .true. restart from an interrupted run. +-------------------------------------------------------------------- +-------------------------------------------------------------------- Variable: electron_phonon Type: CHARACTER Default: ' ' Description: If equal to 'simple' electron-phonon lambda coefficients are computed for a given q and a grid of k-points specified by the variables nk1, nk2, nk3, k1, k2, k3. If equal to 'interpolated' electron-phonon is calculated by interpolation over the Brillouin Zone as in M. Wierzbowska, et al. arXiv:cond-mat/0504077 For metals only, requires gaussian smearing. If trans=.true., the lambdas are calculated in the same run, using the same k-point grid for phonons and lambdas. If trans=.false., the lambdas are calculated using previously saved DeltaVscf in fildvscf, previously saved dynamical matrix, and the present punch file. This allows the use of a different (larger) k-point grid. +-------------------------------------------------------------------- +-------------------------------------------------------------------- Variable: zeu Type: LOGICAL Default: zeu=epsil Description: If .true. in a q=0 calculation for a non metal the effective charges are computed from the dielectric response. This is the default algorithm. If epsil=.true. and zeu=.false. only the dielectric tensor is calculated. +-------------------------------------------------------------------- +-------------------------------------------------------------------- Variable: zue Type: LOGICAL Default: .false. Description: If .true. in a q=0 calculation for a non metal the effective charges are computed from the phonon density responses. This is an alternative algorithm, different from the default one (if trans .and. epsil ) The results should be the same within numerical noise. +-------------------------------------------------------------------- +-------------------------------------------------------------------- Variable: elop Type: LOGICAL Default: .false. Description: If .true. calculate electro-optic tensor. +-------------------------------------------------------------------- +-------------------------------------------------------------------- Variable: fpol Type: LOGICAL Default: .false. Description: If .true. calculate dynamic polarizabilities Requires epsil=.true. ( experimental stage: see example09 for calculation of methane ). +-------------------------------------------------------------------- +-------------------------------------------------------------------- Variable: ldisp Type: LOGICAL Default: .false. Description: If .true. the run calculates phonons for a grid of q-points specified by nq1, nq2, nq3 - for direct calculation of the entire phonon dispersion. +-------------------------------------------------------------------- +-------------------------------------------------------------------- Variable: nogg Type: LOGICAL Default: .false. Description: If .true. disable the "gamma_gamma" trick used to speed up calculations at q=0 (phonon wavevector) if the sum over the Brillouin Zone includes k=0 only. The gamma_gamma trick exploits symmetry and acoustic sum rule to reduce the number of linear response calculations to the strict minimum, as it is done in code phcg.x. This option MUST BE USED if a run with ph.x is to be followed by a run with d3.x for third-order terms calculation. +-------------------------------------------------------------------- +-------------------------------------------------------------------- Variable: ldiag Type: LOGICAL Default: .false. Description: If .true. forces the diagonalization of the dynamical matrix also when only a part of the dynamical matrix has been calculated. It is used together with start_irr and last_irr. If all modes corresponding to a given irreducible representation have been calculated, the phonon frequencies of that representation are correct. The others are zero or wrong. Use with care. +-------------------------------------------------------------------- +-------------------------------------------------------------------- Variable: lqdir Type: LOGICAL Default: .false. Description: If .true. ph.x creates inside outdir a separate subdirectory for each q vector. The flag is set to .true. when ldisp= .true. and fildvscf /= ' ' or when an electron-phonon calculation is performed. The induced potential is saved separately for each q inside the subdirectories. +-------------------------------------------------------------------- +-------------------------------------------------------------------- Variable: search_sym Type: LOGICAL Default: .true. Description: Set it to .false. if you want to disable the mode symmetry analysis. +-------------------------------------------------------------------- +-------------------------------------------------------------------- Variables: nq1, nq2, nq3 Type: INTEGER Default: 0,0,0 Description: Parameters of the Monkhorst-Pack grid (no offset) used when ldisp=.true. Same meaning as for nk1, nk2, nk3 in the input of pw.x. +-------------------------------------------------------------------- +-------------------------------------------------------------------- Variables: nk1, nk2, nk3, k1, k2, k3 Type: INTEGER Default: 0,0,0,0,0,0 Description: When these parameters are specified the phonon program runs a pw non-self consistent calculation with a different k-point grid thant that used for the charge density. This occurs even in the Gamma case. nk1,nk2,nk3 are the parameters of the Monkhorst-Pack grid with offset determined by k1,k2,k3. +-------------------------------------------------------------------- ///--- SPECIFICATION OF IRREDUCIBLE REPRESENTATION +-------------------------------------------------------------------- Variable: start_irr Type: INTEGER Default: 1 See: last_irr Description: Perform calculations only from start_irr to last_irr irreducible representations. IMPORTANT: * start_irr must be <= 3*nat * do not specify "nat_todo" together with "start_irr", "last_irr" +-------------------------------------------------------------------- +-------------------------------------------------------------------- Variable: last_irr Type: INTEGER Default: 3*nat See: start_irr Description: Perform calculations only from start_irr to last_irr irreducible representations. IMPORTANT: * start_irr must be <= 3*nat * do not specify "nat_todo" together with "start_irr", "last_irr" +-------------------------------------------------------------------- +-------------------------------------------------------------------- Variable: nat_todo Type: INTEGER Default: 0, i.e. displace all atoms Description: Choose the subset of atoms to be used in the linear response calculation: "nat_todo" atoms, specified in input (see below) are displaced. Can be used to estimate modes for a molecule adsorbed over a surface without performing a full fledged calculation. Use with care, at your own risk,m and be aware that this is an approximation and may not work. IMPORTANT: * nat_todo <= nat * if linear-response is calculated for a given atom, it should also be done for all symmetry-equivalent atoms, or else you will get incorrect results +-------------------------------------------------------------------- +-------------------------------------------------------------------- Variable: modenum Type: INTEGER Default: 0 Description: For single-mode phonon calculation : modenum is the index of the irreducible representation (irrep) into which the reducible representation formed by the 3*nat atomic displacements are decomposed in order to perform the phonon calculation. Note that a single-mode calculation will not give you the frequency of a single phonon mode: in general, the selected "modenum" is not an eigenvector. What you get on output is a column of the dynamical matrix. +-------------------------------------------------------------------- \\\--- ///--- Q-POINT SPECIFICATION +-------------------------------------------------------------------- Variable: start_q Type: INTEGER Default: 1 See: last_q Description: Used only when ldisp=.true.. Computes only the q points from start_q to last_q. IMPORTANT: * start_q must be <= nqs (number of q points found) * do not specify "nat_todo" together with "start_q", "last_q" +-------------------------------------------------------------------- +-------------------------------------------------------------------- Variable: last_q Type: INTEGER Default: number of q points See: start_q Description: Used only when ldisp=.true.. Computes only the q points from start_q to last_q. IMPORTANT * last_q must be <= nqs (number of q points) * do not specify "nat_todo" together with "start_q", "last_q" +-------------------------------------------------------------------- +-------------------------------------------------------------------- Variable: dvscf_star Type: STRUCTURE Default: disabled Description: It contains the following components: dvscf_star%open (logical, default: .false.) dvscf_star%dir (character, default: outdir//"Rotated_DVSCF" or the ESPRESSO_FILDVSCF_DIR environment variable) dvscf_star%ext (character, default: "dvscf") the extension to use for the name of the output files, see below dvscf_star%basis (character, default: "cartesian") the basis on which the rotated dvscf will be saved dvscf_star%pat (logical, default: true) save an optional file with the displacement patterns and q vector for each dvscf file IF dvscf_star%open is .true. use symmetry to compute and store the variation of the self-consistent potential on every q* in the star of the present q. The rotated dvscf will then be stored in directory dvscf_star%dir with name prefix.dvscf_star%ext.q_name//"1". Where q_name is derived from the coordinates of the q-point, expressed as fractions in crystalline coordinates (notice that ph.x reads q-points in cartesian coordinates). E.g. q_cryst= (0, 0.5, -0.25) -> q_name = "0_1o2_-1o4" The dvscf can be represented on a basis of cartesian 1-atom displacements (dvscf_star%basis='cartesian') or on the basis of the modes at the rotated q-point (dvscf_star%basis='modes'). Notice that the el-ph wannier code requires 'cartesian'. Each dvscf file comes with a corresponding pattern file with an additional ".pat" suffix; this file contains information about the basis and the q-point of the dvscf. Note: rotating dvscf can require a large amount of RAM memory and can be i/o intensive; in its current implementation all the operations are done on a single processor. Note2: this feature is currently untested with image parallelisation. +-------------------------------------------------------------------- +-------------------------------------------------------------------- Variable: drho_star Type: STRUCTURE See: dvscf_star Default: disabled Description: It contains the following components: drho_star%open (logical, default: .false.) drho_star%dir (character, default: outdir//"Rotated_DRHO" or the ESPRESSO_FILDRHO_DIR environment variable) drho_star%ext (character, default: "drho") the extension to use for the name of the output files, see below drho_star%basis (character, default: "modes") the basis on which the rotated drho will be saved drho_star%pat (logical, default: false) save an optional file with the displacement patterns and q vector for each drho file Like dvscf_star, but for the perturbation of the charge density. Notice that the defaults are different. +-------------------------------------------------------------------- \\\--- ===END OF NAMELIST====================================================== ======================================================================== Line of input: xq(1) xq(2) xq(3) DESCRIPTION OF ITEMS: +-------------------------------------------------------------------- Variables: xq(1) xq(2) xq(3) Type: REAL Description: The phonon wavevector, in units of 2pi/a0 (a0 = lattice parameter). Not used if ldisp=.true. +-------------------------------------------------------------------- ===End of line-of-input================================================= ________________________________________________________________________ * IF nat_todo was specified : ======================================================================== Line of input: atom(1) atom(2) ... atom(nat_todo) DESCRIPTION OF ITEMS: +-------------------------------------------------------------------- Variables: atom(1) atom(2) ... atom(nat_todo) Type: INTEGER Description: Contains the list of indices of atoms used in the calculation if "nat_todo" is specified. +-------------------------------------------------------------------- ===End of line-of-input================================================= ENDIF ________________________________________________________________________ :::: ADDITIONAL INFORMATION NB: The program ph.x writes on the tmp_dir/_ph0/{prefix}.phsave directory a file for each representation of each q point. This file is called data-file.#iq.#irr.xml where #iq is the number of the q point and #irr is the number of the representation. These files contain the contribution to the dynamical matrix of the irr representation for the iq point. If recover=.true. ph.x does not recalculate the representations already saved in the tmp_dir/_ph0/{prefix}.phsave directory. Moreover ph.x writes on the files data-file.#iq.xml in the tmp_dir/_ph0/{prefix}.phsave directory the displacement patterns that it is using. If recover=.true. ph.x does not recalculate the displacement patterns found in the tmp_dir/_ph0/{prefix}.phsave directory. This mechanism allows: 1) To recover part of the ph.x calculation even if the recover file or files are corrupted. You just remove the _ph0/{prefix}.recover files from the tmp_dir directory. You can also remove all the _ph0 files and keep only the _ph0/{prefix}.phsave directory. 2) To split a phonon calculation into several jobs for different machines (or set of nodes). Each machine calculates a subset of the representations and saves its data-file.#iq.#irr.xml files on its tmp_dir/_ph0/{prefix}.phsave directory. Then you collect all the data-file.#iq.#irr.xml files in one directory and run ph.x to collect all the dynamical matrices and diagonalize them. NB: To split the q points in different machines, use the input variables start_q and last_q. To split the irreducible representations, use the input variables start_irr, last_irr. Please note that different machines will use, in general, different displacement patterns and it is not possible to recollect partial dynamical matrices generated with different dispacement patterns. A calculation split into different machines will run as follows: A preparatory run of ph.x with start_irr=0, last_irr=0 produces the sets of displacement patterns and save them on the data-file.#iq.xml files. These files are copied in all the tmp_dir/_ph0/{prefix}.phsave directories of the machines where you plan to run ph.x. ph.x is run in different machines with complementary sets of start_q, last_q, start_irr and last_irr variables. All the files data-file.#iq.#irr.xml are collected on a single tmp_dir/_ph0/{prefix}.phsave directory (remember to collect also data-file.#iq.0.xml). A final run of ph.x in this machine collects all the data contained in the files and diagonalizes the dynamical matrices. This is done requesting a complete dispersion calculation without using start_q, last_q, start_irr, or last_irr. See an example in examples/GRID_example. On parallel machines the q point and the irreps calculations can be split automatically using the -nimage flag. See the phonon user guide for further information.