Henkelman Groupが配布しているプログラムを利用してBader電荷の計算を行う。
以下ではノルム保存擬ポテンシャルC_pbe6TMを用いる。
入力ファイル
0 0 0 0 0 0 8.0000 20.0000 1 2 2 : GMAX, GMAXP, NTYP, NATM, NATM2 191 0 : number of space group, type of bravis lattice 4.655538364 4.655538364 20.000 90.0 90.0 120.0 : a,b,c,alpha,beta,gamma 24 24 1 1 1 1 : knx,kny,knz, k-point shift 0 0 : NCORD, NINV, : IWEI, IMDTYP, ITYP 0.6666666666 0.3333333333 0.0000000000 1 1 1 0.3333333333 0.6666666666 0.0000000000 1 1 1 6 0.1500 12.0107 1 1 0.d0 : TYPE 1IATOMN,ALFA,AMION,ILOC,IVAN 0 0 0 0 0 : ICOND 0-MD, 1-CONT.MD, 2-WAVE FN,, 3-WAVE FN CONT., iconstpw 0 1 : IPRE, IPRI 200 200 0 3600.00 0 : NMD1, NMD2, iter_last, CPUMAX,ifstop 3 1 : Simple=1,Broyd2=3,Blugel=6, 1:charge, 2:potential mix. 0 20 0.8 : starting mixing, kbxmix,alpha 0.60 0.50 0.60 0.70 1.00 : DTIM1, DTIM2, DTIM3, DTIM4, dtim_last 30.00 2 1 0.10D-08 1.d-06 : DTIO ,IMDALG, IEXPL, EDELTA -0.0010 0.10D+02 0 : WIDTH,FORCCR,ISTRESS ggapbe 1 : XCTYPE, nspin 1.00 3 : destm, n_stm 101 : NBZTYP 0-SF, 1-BK, 2-SC, 3-BCC, 4-FCC, 5-DIA, 6-HEX 0 0 0 : NKX, NKY, NKZ 0 0 0 : NKX2,NKY2,NKZ2 8 : NEG 1 : NEXTST(MB) 0 : 0; random numbers, 1; matrix diagon 2 0 0 0(MB) : imsd, i_2lm, i_sd2another, wksz for phase 0 : evaluation of eko difference.0 = no ,1 = yes 0 : npdosao 0 0.0 : SM_N, DOPPING
計算結果
$ grep ETOT your_output_file_name|grep "[0-9]" ETOT: 1 15.49339609 0.1549E+02 0.4996E-01 ETOT: 2 0.34620940 0.1515E+02 0.1209E-01 ETOT: 3 -5.83837125 0.6185E+01 0.1717E-01 ETOT: 4 -8.60080202 0.2762E+01 0.1845E-01 ETOT: 5 -10.11782100 0.1517E+01 0.2536E-01 ETOT: 6 -11.03537609 0.9176E+00 0.2397E-01 ETOT: 7 -11.40509046 0.3697E+00 0.2251E-01 ETOT: 8 -11.45549051 0.5040E-01 0.2050E-01 ETOT: 9 -11.48179862 0.2631E-01 0.1827E-01 ETOT: 10 -11.47035224 0.1145E-01 0.1958E-01 ETOT: 11 -11.53852896 0.6818E-01 0.1092E-01 ETOT: 12 -11.57400237 0.3547E-01 0.4760E-02 ETOT: 13 -11.58514681 0.1114E-01 0.1420E-02 ETOT: 14 -11.58579130 0.6445E-03 0.5748E-03 ETOT: 15 -11.58587175 0.8045E-04 0.1339E-03 ETOT: 16 -11.58587362 0.1875E-05 0.4189E-04 ETOT: 17 -11.58587413 0.5126E-06 0.1486E-04 ETOT: 18 -11.58587420 0.6892E-07 0.3361E-05 ETOT: 19 -11.58587421 0.4461E-08 0.1102E-05 ETOT: 20 -11.58587421 0.1802E-08 0.3413E-06 ETOT: 21 -11.58587421 0.2176E-09 0.1103E-06 ETOT: 22 -11.58587421 0.3718E-10 0.4886E-07 ETOT(Q) + SM_energy = -11.5858742100388 8.35680549919333
icond=9として再計算して実空間の電荷密度nfchgt_r.dataを作成する。
/home/hamada/STATE/tools/ChargeUtil/chg2cubeを用いて電荷密度をGaussian cube形式に変換する。
$ chg2cube Enter the name of the STATE input file> your_input_file_name Enter the name of the charge density file> nfchgt_r.data Enter the prefix for output file(s)> charge reading nfchgt_r.data...done. # of data in nfchgt_r.data : 1 data #1 : ispin : 1 : ilevel: 1 Creating charge.cube...done. Program successfully ended
chg2cubeの実行後、対話的に
Gaussian cube形式に関しては例えばここを参照。
上で得られたGaussian cube形式の電荷密度ファイルcharge.cubeを用いてBader電荷を計算する。
$ bader charge.cube GRID BASED BADER ANALYSIS (Version 0.95a 02/26/16) OPEN ... charge.cube GAUSSIAN-STYLE INPUT FILE FFT-grid: 30 x 30 x 128 CLOSE ... charge.cube RUN TIME: 0.03 SECONDS CALCULATING BADER CHARGE DISTRIBUTION 0 10 25 50 75 100 PERCENT DONE: ********************** REFINING AUTOMATICALLY ITERATION: 1 EDGE POINTS: 23177 REASSIGNED POINTS: 969 ITERATION: 2 CHECKED POINTS: 9850 REASSIGNED POINTS: 0 RUN TIME: 0.15 SECONDS CALCULATING MINIMUM DISTANCES TO ATOMS 0 10 25 50 75 100 PERCENT DONE: ********************** RUN TIME: 0.01 SECONDS WRITING BADER ATOMIC CHARGES TO ACF.dat WRITING BADER VOLUME CHARGES TO BCF.dat NUMBER OF BADER MAXIMA FOUND: 6 SIGNIFICANT MAXIMA FOUND: 6 VACUUM CHARGE: 0.0205 NUMBER OF ELECTRONS: 8.00003
プログラムbaderのオプションはbader -hで確認できる:
$ bader -h GRID BASED BADER ANALYSIS (Version 0.95a 02/26/16) Description of flags -c | -n < bader | voronoi > Turn on [-c] or off [-n] the following calculations bader: Bader atoms in molecules (default) voronoi: population analysis based on distance -b < neargrid | ongrid | weight > Use the default near-grid bader partitioning, the original on-grid based algorithm, or the weight method of Yu and Trinkle -r < refine_edge_method > By default (-r -1) , only the points around reassigned points are checked during refinements. The old method, which checks every edge point during each refinement, can be enabled using the -r -2 switch: bader -r -2 CHGCAR -ref < reference_charge > Use a reference charge file to do the Bader partitioning. This is the recommended way to analyze vasp output files: bader CHGCAR -ref CHGCAR_total where CHGCAR_total is the sum of AECCAR0 and AECCAR2. -vac < off | auto | vacuum_density > Assign low density points to vacuum. auto: vacuum density cutoff is 1E-3 e/Ang^3 by default off: do not assign low density points to a vacuum volume vacuum_density: maximum density assigned to a vacuum volume -m < known | max > Determines how trajectories terminate known: stop when a point is surrounded by known points max: stop only when a charge density maximum is reached -p < all_atom | all_bader > Print calculated Bader volumes all_atom: all atomic volumes all_bader: all Bader volumes -p < sel_atom | sel_bader > <volume list or range> Print calculated Bader volumes sel_atom: atomic volume(s) around the selected atom(s) sel_bader: selected Bader volumes -p < sum_atom | sum_bader > <volume list or range> Print calculated Bader volumes sum_atom: sum of atomic volume(s) around the selected atom(s) sum_bader: sum of selected Bader volumes -p < atom_index | bader_index > Print index of atomic or Bader volumes atom_index: print atomic volume indicies bader_index: print Bader volume indicies -i < cube | chgcar > Input charge density file type. If not specified, the program will try to determine the charge density file type automatically. -h Help. -v Verbose output. -cp Find critical points of the charge density Calculate eigenvalues and eigenvectors at those points Store results in file named CPF.dat
Bader電荷の計算結果はACF.datに出力される:
$ cat ACF.dat # X Y Z CHARGE MIN DIST ATOMIC VOL -------------------------------------------------------------------------------- 1 2.3277690 1.3439380 0.0000000 3.9020033 1.0751426 65.2790699 2 0.0000000 2.6878760 0.0000000 4.0774900 1.2120244 69.3785643 -------------------------------------------------------------------------------- VACUUM CHARGE: 0.0205 VACUUM VOLUME: 240.7492 NUMBER OF ELECTRONS: 8.0000
CHARGEに各原子の電荷が表示される。単位胞内の2つの炭素原子は等価なのに電荷に偏りが生じているのは、電荷密度のグリッドが粗いためと考えられる。
エネルギーカットオフを増加させて(電荷密度のグリッドを細かくして)電荷分布の収束性を調べる。
gmaxp | 20 | 30 | 40 | 50 | 60 | 70 | 80 | 90 | 100 |
grid-X | 30 | 48 | 60 | 80 | 90 | 108 | 120 | 144 | 150 |
grid-Y | 30 | 48 | 60 | 80 | 90 | 108 | 120 | 144 | 150 |
grid-Y | 128 | 192 | 256 | 320 | 384 | 450 | 512 | 576 | 640 |
炭素原子1の電荷 | 3.902 | 3.934 | 3.945 | 3.956 | 3.960 | 3.965 | 3.967 | 3.971 | 3.972 |
炭素原子2の電荷 | 4.077 | 4.044 | 4.034 | 4.022 | 4.019 | 4.014 | 4.011 | 4.008 | 4.007 |
電荷の偏り | 0.175 | 0.110 | 0.088 | 0.066 | 0.059 | 0.049 | 0.044 | 0.037 | 0.035 |
カットオフの増加とともに電荷の偏りが減少し精度が向上していることが確認できる。
入力ファイル
0 0 0 0 0 0 8.0000 20.0000 1 4 4 : GMAX, GMAXP, NTYP, NATM, NATM2 1 0 : number of space group, type of bravis lattice 8.063628983 4.655538364 20.000 90.0 90.0 90.0 : a,b,c,alpha,beta,gamma 12 24 1 1 1 1 : knx,kny,knz, k-point shift 1 0 : NCORD, NINV, : IWEI, IMDTYP, ITYP 1.3439381638 0.0000000000 0.0000000000 1 1 1 -1.3439381638 0.0000000000 0.0000000000 1 1 1 2.6878763276 2.3277691820 0.0000000000 1 1 1 -2.6878763276 2.3277691820 0.0000000000 1 1 1 6 0.1500 12.0107 1 1 0.d0 : TYPE 1IATOMN,ALFA,AMION,ILOC,IVAN 0 0 0 0 0 : ICOND 0-MD, 1-CONT.MD, 2-WAVE FN,, 3-WAVE FN CONT., iconstpw 0 1 : IPRE, IPRI 200 200 0 3600.00 0 : NMD1, NMD2, iter_last, CPUMAX,ifstop 3 1 : Simple=1,Broyd2=3,Blugel=6, 1:charge, 2:potential mix. 0 20 0.8 : starting mixing, kbxmix,alpha 0.60 0.50 0.60 0.70 1.00 : DTIM1, DTIM2, DTIM3, DTIM4, dtim_last 100.00 2 1 0.10D-08 1.d-06 : DTIO ,IMDALG, IEXPL, EDELTA -0.0010 0.10D-02 0 : WIDTH,FORCCR,ISTRESS ggapbe 1 : XCTYPE, nspin 1.00 3 : destm, n_stm 101 : NBZTYP 0-SF, 1-BK, 2-SC, 3-BCC, 4-FCC, 5-DIA, 6-HEX 0 0 0 : NKX, NKY, NKZ 0 0 0 : NKX2,NKY2,NKZ2 24 : NEG 1 : NEXTST(MB) 0 : 0; random numbers, 1; matrix diagon 2 0 0 0(MB) : imsd, i_2lm, i_sd2another, wksz for phase 0 : evaluation of eko difference.0 = no ,1 = yes 0 : npdosao 0 0.0 : SM_N, DOPPING
計算結果
$ grep ETOT nfout_1|grep "[0-9]" ETOT: 1 26.21341351 0.2621E+02 0.3937E-01 ETOT: 2 -5.07267018 0.3129E+02 0.1212E-01 ETOT: 3 -15.33757551 0.1026E+02 0.1318E-01 ETOT: 4 -19.66071003 0.4323E+01 0.1333E-01 ETOT: 5 -22.00674384 0.2346E+01 0.1766E-01 ETOT: 6 -22.88457509 0.8778E+00 0.1587E-01 ETOT: 7 -22.92511351 0.4054E-01 0.1501E-01 ETOT: 8 -22.97540886 0.5030E-01 0.1372E-01 ETOT: 9 -22.95949325 0.1592E-01 0.1391E-01 ETOT: 10 -22.97376104 0.1427E-01 0.1353E-01 ETOT: 11 -23.04325978 0.6950E-01 0.9979E-02 ETOT: 12 -23.15572141 0.1125E+00 0.3768E-02 ETOT: 13 -23.16991809 0.1420E-01 0.1487E-02 ETOT: 14 -23.17160528 0.1687E-02 0.4518E-03 ETOT: 15 -23.17172043 0.1151E-03 0.1618E-03 ETOT: 16 -23.17173717 0.1673E-04 0.7242E-04 ETOT: 17 -23.17174331 0.6144E-05 0.2139E-04 ETOT: 18 -23.17174360 0.2898E-06 0.7831E-05 ETOT: 19 -23.17174357 0.3402E-07 0.3759E-05 ETOT: 20 -23.17174366 0.8909E-07 0.2707E-05 ETOT: 21 -23.17174376 0.1035E-06 0.1720E-05 ETOT: 22 -23.17174377 0.1106E-07 0.1275E-05 ETOT: 23 -23.17174379 0.1527E-07 0.1788E-05 ETOT: 24 -23.17174380 0.1140E-07 0.6630E-06 ETOT: 25 -23.17174380 0.3104E-08 0.3894E-06 ETOT: 26 -23.17174380 0.7199E-09 0.2579E-06 ETOT: 27 -23.17174380 0.6648E-10 0.5746E-07 ETOT(Q) + SM_energy = -23.1717438004519 16.7136110440348
gmaxp | 20 | 40 | 60 | 80 | 100 |
grid-X | 54 | 108 | 160 | 216 | 270 |
grid-Y | 30 | 60 | 90 | 120 | 150 |
grid-Y | 128 | 256 | 384 | 512 | 640 |
炭素原子1の電荷 | 3.890 | 3.967 | 3.956 | 3.975 | 3.969 |
炭素原子2の電荷 | 4.088 | 4.011 | 4.023 | 4.023 | 4.009 |
炭素原子3の電荷 | 4.088 | 4.011 | 4.023 | 4.023 | 4.009 |
炭素原子4の電荷 | 3.890 | 3.967 | 3.956 | 3.975 | 3.969 |
電荷の偏り | 0.198 | 0.043 | 0.066 | 0.027 | 0.039 |