This file describes the contents of the tarballs and lists compatible version of the software they relate to. DFT.tar.bz2 (in dft.zip) =========== This tarball contains files from the DFT calculations in which: - the primitive cell was relaxed at a fixed external pressure within DFT, - the supercell lattice vectors were chosen so as to minimize the finite size errors in the subsequent QMC calculations, and - the k-vector offset at which to perform QMC wave function optimization was chosen. The tarball consists of a root diretory named DFT, containing subdirectories named //. The DFT directory contains the following files: - ///*.supercell: Summary of the resulting supercell parameters in human-readable form. The supercell lattice vectors and supercell matrix were determined from the primitive lattice vectors using the 'supercell' CASINO utility. - ///Offsets/hydrogen.cell ///Offsets/hydrogen.param Base CASTEP input files used for the determination of the optimal k-offset. - ///Offsets/kvectors.txt Human-readable summary of the process of determining the optimal twist angle for the QMC wave function optimization stage. In this process we evaluated the DFT energies obtained with a k-point grid commensurate with the supercell offset by each of the 8 inequivalent twist angles which result in a real-valued wave function, compared them with the DFT energy obtained using a fine k-point grid, and we picked the twist angle which minimized this difference. The twist angles and energies are listed in the file. - ///Calcs/hydrogen.cell ///Calcs/hydrogen.param CASTEP input files used for the generation of the plane-wave orbitals for QMC runs. Not included in this tarball are the CASTEP *recpot files which are part of CASTEP, CASTEP output files which were dynamically handled and whose results are summarized instead, and resulting DFT orbital files used in the QMC runs due to size considerations. VMC.tar.bz2 (in vmc.zip) =========== This tarball contains files from the VMC wave function optimization runs which determined the Jastrow factor and backflow parameters used in the subsequent DMC calculations. The tarball consists of a root diretory named VMC, containing subdirectories named //. The VMC directory contains the following files: - ///sj/input ///sj/cdata.0 Base CASINO input file for the optimization of an SJ wave function, and initial correlation.data parameter file representing an "empty" Jastrow correlation factor. - ///sj/out.1 ///sj/cdata.1 CASINO output file for an optimization run consisting of two cycles of mean-absolute-deviation-from-the-median minimization (MADmin) with cut-off lengths held fixed, and resulting correlation.data parameter file after this stage. - ///sj/out.2 ///sj/cdata.2 CASINO output file for an optimization run consisting of one MADmin cycle with cut-off lengths allowed to vary, and resulting correlation.data parameter file after this stage. - ///sj/out.3 ///sj/cdata.3 ///sj/correlation.data CASINO output file for an optimization run consisting of one energy minimization (Emin) cycle with cut-off lengths held fixed, and resulting correlation.data parameter file after this stage. - ///bf/input ///bf/cdata.0 ///bf/out.1 ///bf/cdata.1 ///bf/out.2 ///bf/cdata.2 ///bf/out.3 ///bf/cdata.3 ///bf/correlation.data (For N=96 only) Analogous to the above; CASINO input, output and parameter files for the optimization of an SJB wave function starting from the optimized SJ wave function. The three optimization stages are: - 1 MADmin cycle with cut-off lengths held fixed - 2 MADmin cycles with cut-off lengths allowed to vary - 1 Emin cycle with cut-off lengths held fixed - /results.txt Human-readable summary of optimization results and basic quality checks. Not included in this tarball are the DFT orbital files, due to size considerations. DMC.tar.bz2 (in dmc.zip) =========== This tarball contains files from the twist-averaged DMC runs and finite-size correction calculations from which our final results were drawn. The tarball consists of a root diretory named DMC, containing subdirectories named //. The DMC directory contains the following files: - ///twist/SJDMC_dt/input ///twist/SJDMC_dt/correlation.data ///twist/SJDMC_dt/out* Base CASINO input file, wave-function parameter file, and per-stage output files for the th twist of the twist-averaged DMC calculation with timestep . - ///twist/SJDMC_dt/reblock.results Human-readable summary of the statistical reblocking analysis performed on the DMC data for each twist and timestep, containing the data used in our final results. - ///twist/SJDMC_dt
/finsize.log (N=768 only.) Human-readable summary of the evaluation of the contribution of the twists to the finite size correction to the exchange-correlation energy, computed from the static structure factor evaluated during the DMC calculation. - ///twist/SJDMC_dt
/TWIST_IGNORED_FOR_XC_CORRECTION_DUE_TO_TRUNCATED_FILE (N=768 only.) Empty file to flag absence of finsize.log for a given twist, which is ignored in the XC correction for technical reasons. - ///twist/E_SJDMC_dt0.dat Human-readable text file containing the zero-timestep extrapolation of the DMC energy and its errorbar for each twist. - ///twist/hydrogen.castep CASTEP output files detailing the generation of the DFT orbitals for use in DMC and the evaluation of the DFT energy at the given twist using the PBE functional. - ///twist/hydrogen_kzk.castep CASTEP output files detailing the evaluation of the DFT energy at the given twist using the KZK functional. - ///twistav_fit.results Human readable summary of the fit performed to obtain the twist-averaged DMC energy. - ///PBE_fine/hydrogen.cell ///PBE_fine/hydrogen.param ///PBE_fine/hydrogen.castep ///LDA_fine/hydrogen.cell ///LDA_fine/hydrogen.param ///LDA_fine/hydrogen.castep ///KZK_fine/hydrogen.cell ///KZK_fine/hydrogen.param ///KZK_fine/hydrogen.castep CASTEP input and output files for DFT using fine k-point grids with the PBE, LDA and KZK functionals. - ///PBE_twistinfo/hydrogen.cell ///PBE_twistinfo/hydrogen.param ///PBE_twistinfo/STATUS ///KZK_twistinfo/hydrogen.cell ///KZK_twistinfo/hydrogen.param ///KZK_twistinfo/STATUS CASTEP input files and log of process of generation of DFT orbitals and evaluation of the DFT energy at the different twists using the PBE and KZK functionals; the CASTEP output files corresponding to these DFT runs are the hydrogen.castep and hydrogen_kzk.castep files detailed above. - ///KE_corr/hydrogen.cell ///KE_corr/hydrogen.param ///KE_corr/hydrogen.castep (N=768 only.) CASTEP input and output files correspoding to the generation of DFT orbitals for the QMC evaluation of the finite size correction to the kinetic energy. - ///KE_corr/input ///KE_corr/correlation.data ///KE_corr/out (N=768 only.) CASINO input, wave function parameter and output files for the QMC evaluation of the finite size correction to the kinetic energy. - ///E_SJDMC_dt0_v_twist.dat Text file with lines of the format: where is the "naive" DMC statistical error, and also accounts for the error due to the random sampling of k-space. - ///E_SJDMC_dt0_twistav.dat ///E_SJDMC_dt0_twistav_kerror.dat ///E_SJDMC_dt0_KZKcorr.dat ///E_SJDMC_dt0_KZKcorr_kerror.dat Text files giving final results, namely the twist averaged DMC energy and error bar, the twist averaged DMC energy and error bar including k-sampling random error, the KZK-corrected twist-averaged DMC energy and error bar, and the KZK-corrected twist-averaged DMC energy, respectively. - //E_SJDMC_dt0_KZKcorr_v_V.dat //E_SJDMC_dt0_KZKcorr_v_V_kerror.dat //E_SJDMC_dt0_twistav_v_V.dat //E_SJDMC_dt0_twistav_v_V_kerror.dat Text files plotting the respective results (as described above) against volume. - //virial_p_v_V.dat Text file plotting the pressure derived from the above data and the virial theorem, including error bar, against volume. - //ke_corr_v_V.dat //xc_corr_v_V.dat (N=768 only.) Finite size corrections to the kinetic and exchange-correlation energies, respectively, plotted as a function of volume. The XC correction plot includes statistical error bars. For the select cases where backflow DMC calculations were performed, files named like their Slater-Jastrow counterparts replacing "SJDMC" with "SJBDMC" contain the relevant results. Not included in the tarball are the CASTEP *recpot files which are part of CASTEP, the DFT orbital files, and the CASINO output files containing the raw DMC local energies and expectation values, due to size considerations, and summaries are given instead. Anharmonic.tar.bz2 (in anharmonic.zip) ================== This tarball countains files from the DFT-based evaluation of the anharmonic vibrational corrections used in our final results. The tarball consists of a root directory named Anharmonic, containing subdirectories with raw data. The Anharmonic directory contains the following files: - BO_energy_surfaces/_.dat Born-Oppenheimer energy surfaces calculated using CASTEP, used as input for the CAESAR anharmonic corrections research code. Each file contains one data block for each symmetry-inequivalent mode in the crystal, where the first line gives the harmonic frequency of the mode (a.u.) and each subsequent line gives the amplitude of the mode (a.u.) and the corresponding DFT energy (eV). - anharmonic_corrections.dat Final anharmonic corrections (eV/atom) vs pressure (GPa) obtained from the CAESAR anharmonic corrections research code. Not included in this tarball are the CASTEP input and output files, which were generated dynamically. Software versions ================= - CASTEP files are compatible with CASTEP version 6.11 and later. For information on how to get a copy of CASTEP visit: http://www.castep.org - CASINO files are compatible with CASINO version 2.12 and later. For information on how to get a copy of CASINO visit: http://vallico.net/casinoqmc/ - For information on the CAESAR anharmonic corrections research code email bm418 at cam.ac.uk.