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几何结构优化时能量震荡，如何处理？ 已有1人参与
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现在做的掺杂体系，12.5%，25%，50%，其中12.5%，50%都能收敛，就是25%不能收敛，什么原因呢？ 不太可能是结构不合理吧，毕竟两边浓度都成功了。请大家指教。 像这种能量震荡的该如何调试呢？  castep文件：几何优化只有一个yes，3个no。 +------------+-------------+-------------+-----------------+ <-- min BFGS | Step | lambda | F.delta | enthalpy | <-- min BFGS +------------+-------------+-------------+-----------------+ <-- min BFGS | previous | 0.000000 | 0.002781 | -29834.670729 | <-- min BFGS | trial step | 1.000000 | 0.001926 | -29834.776186 | <-- min BFGS | line step | 3.251631 | -0.003682 | -29837.973701 | <-- min BFGS | quad step | 1.773369 | -0.002702 | -29838.006664 | <-- min BFGS +------------+-------------+-------------+-----------------+ <-- min BFGS BFGS: finished iteration 100 with enthalpy= -2.98380067E+004 eV +-----------+-----------------+-----------------+------------+-----+ <-- BFGS | Parameter | value | tolerance | units | OK? | <-- BFGS +-----------+-----------------+-----------------+------------+-----+ <-- BFGS | dE/ion | 8.339837E-002 | 5.000000E-005 | eV | No | <-- BFGS | |F|max | 1.288961E-001 | 1.000000E-001 | eV/A | No | <-- BFGS | |dR|max | 6.082554E-004 | 5.000000E-003 | A | Yes | <-- BFGS | Smax | 4.065663E+000 | 2.000000E-001 | GPa | No | <-- BFGS +-----------+-----------------+-----------------+------------+-----+ <-- BFGS BFGS : WARNING - Geometry optimization failed to converge after 100 steps ================================================================================ BFGS : Final Configuration: ================================================================================ ------------------------------- Unit Cell ------------------------------- Real Lattice(A) Reciprocal Lattice(1/A) 7.8142248 0.0000000 0.0000000 0.8040702 0.0000000 0.0000000 0.0000000 7.8142248 0.0000000 0.0000000 0.8040702 0.0000000 0.0000000 0.0000000 8.1112610 0.0000000 0.0000000 0.7746250 Lattice parameters(A) Cell Angles a = 7.814225 alpha = 90.000000 b = 7.814225 beta = 90.000000 c = 8.111261 gamma = 90.000000 Current cell volume = 495.290711 A**3 ------------------------------- Cell Contents ------------------------------- xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx x Element Atom Fractional coordinates of atoms x x Number u v w x x----------------------------------------------------------x x O 1 0.000000 0.000000 0.043401 x x O 2 0.000000 0.000000 0.516500 x x O 3 0.000000 0.243773 0.271102 x x O 4 0.000000 -0.248546 0.775364 x x O 5 0.000000 -0.243773 0.271102 x x O 6 0.000000 0.248546 0.775364 x x O 7 -0.243773 0.000000 0.271102 x x O 8 0.248546 0.000000 0.775364 x x O 9 0.243773 0.000000 0.271102 x x O 10 -0.248546 0.000000 0.775364 x x O 11 0.500000 0.000000 0.021770 x x O 12 0.500000 0.000000 0.520766 x x O 13 0.000000 0.500000 0.021770 x x O 14 0.000000 0.500000 0.520766 x x O 15 0.500000 0.250430 0.283155 x x O 16 0.500000 -0.257225 0.761425 x x O 17 -0.500000 -0.250430 0.283155 x x O 18 -0.500000 0.257225 0.761425 x x O 19 -0.250430 0.500000 0.283155 x x O 20 0.257225 0.500000 0.761425 x x O 21 0.250430 -0.500000 0.283155 x x O 22 -0.257225 -0.500000 0.761425 x x O 23 0.500000 0.500000 0.024175 x x O 24 0.500000 0.500000 0.533453 x x Na 1 -0.250144 0.250144 0.498527 x x Na 2 0.250144 -0.250144 0.498527 x x Na 3 -0.250144 -0.250144 0.498527 x x Na 4 0.250144 0.250144 0.498527 x x K 1 -0.248651 -0.248651 0.003625 x x K 2 0.248651 0.248651 0.003625 x x K 3 0.248651 -0.248651 0.003625 x x K 4 -0.248651 0.248651 0.003625 x x Fe 1 0.000000 0.000000 0.255229 x x Fe 2 0.500000 0.500000 0.744987 x x Nb 1 0.000000 0.000000 0.741251 x x Nb 2 0.500000 0.000000 0.252241 x x Nb 3 0.500000 0.000000 0.748703 x x Nb 4 0.000000 0.500000 0.252241 x x Nb 5 0.000000 0.500000 0.748703 x x Nb 6 0.500000 0.500000 0.249257 x xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx BFGS : Final Enthalpy = -2.98380067E+004 eV BFGS : Final <frequency> = 7075.84270 cm-1 BFGS : Final bulk modulus unchanged from initial value ********************************************************** *** There were at least 1 warnings during this run *** *** => please check the whole of this file carefully! *** ********************************************************** ***************************** Symmetrised Forces ***************************** * * * Cartesian components (eV/A) * * -------------------------------------------------------------------------- * * x y z * * * * O 1 0.00000 0.00000 -0.01499 * * O 2 0.00000 0.00000 0.05276 * * O 3 0.00000 0.05652 -0.01386 * * O 4 0.00000 -0.03243 -0.01695 * * O 5 0.00000 -0.05652 -0.01386 * * O 6 0.00000 0.03243 -0.01695 * * O 7 -0.05652 0.00000 -0.01386 * * O 8 0.03243 0.00000 -0.01695 * * O 9 0.05652 0.00000 -0.01386 * * O 10 -0.03243 0.00000 -0.01695 * * O 11 0.00000 0.00000 0.02100 * * O 12 0.00000 0.00000 -0.00609 * * O 13 0.00000 0.00000 0.02100 * * O 14 0.00000 0.00000 -0.00609 * * O 15 0.00000 -0.00585 -0.03748 * * O 16 0.00000 0.08450 -0.01428 * * O 17 0.00000 0.00585 -0.03748 * * O 18 0.00000 -0.08450 -0.01428 * * O 19 0.00585 0.00000 -0.03748 * * O 20 -0.08450 0.00000 -0.01428 * * O 21 -0.00585 0.00000 -0.03748 * * O 22 0.08450 0.00000 -0.01428 * * O 23 0.00000 0.00000 0.00823 * * O 24 0.00000 0.00000 0.03740 * * Na 1 0.06417 -0.06417 0.09154 * * Na 2 -0.06417 0.06417 0.09154 * * Na 3 0.06417 0.06417 0.09154 * * Na 4 -0.06417 -0.06417 0.09154 * * K 1 -0.02515 -0.02515 -0.01297 * * K 2 0.02515 0.02515 -0.01297 * * K 3 0.02515 -0.02515 -0.01297 * * K 4 -0.02515 0.02515 -0.01297 * * Fe 1 0.00000 0.00000 -0.08922 * * Fe 2 0.00000 0.00000 -0.07155 * * Nb 1 0.00000 0.00000 0.04927 * * Nb 2 0.00000 0.00000 0.01781 * * Nb 3 0.00000 0.00000 -0.02764 * * Nb 4 0.00000 0.00000 0.01781 * * Nb 5 0.00000 0.00000 -0.02764 * * Nb 6 0.00000 0.00000 0.03392 * * * ****************************************************************************** *********** Symmetrised Stress Tensor *********** * * * Cartesian components (GPa) * * --------------------------------------------- * * x y z * * * * x -4.065663 0.000000 0.000000 * * y 0.000000 -4.065663 0.000000 * * z 0.000000 0.000000 0.306267 * * * * Pressure: 2.6084 * * * ************************************************* Pseudo atomic calculation performed for O 2s2 2p4 Converged in 23 iterations to a total energy of -428.2520 eV Pseudo atomic calculation performed for Na 2s2 2p6 3s1 Converged in 21 iterations to a total energy of -1298.1443 eV Pseudo atomic calculation performed for K 3s2 3p6 4s1 Converged in 23 iterations to a total energy of -777.4801 eV Pseudo atomic calculation performed for Fe 3d6 4s2 Converged in 32 iterations to a total energy of -849.3473 eV Pseudo atomic calculation performed for Nb 4s2 4p6 4d4 5s1 Converged in 21 iterations to a total energy of -1537.8413 eV Charge spilling parameter for spin component 1 = 0.28% Charge spilling parameter for spin component 2 = 0.28% |
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4楼2016-06-02 09:31:01
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这个可能是因为你结构不合理，原子偏离平衡位置太远了，所以一直在震荡，你试一下手动调低精度，或者，如果原子位置不好调节，那你试下改变abc的值，然后再优化看看 发自小木虫Android客户端 |
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小雨熊
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5楼2016-06-02 15:19:17
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感谢您的回复： 1.我就是觉得构型不应该有问题啊，因为同样的构型12.5%和50%两种浓度都可以成功，唯独中间浓度25%不行。如图，就是Fe取代b位铌。  2.您的意思把截断能，smearing都调小一点吗？事实上我就是用的coarse精度，还需要调小吗？k点呢？ 3.设置： *********************** Exchange-Correlation Parameters *********************** using functional : Local Density Approximation Divergence correction : off DFT+D: Semi-empirical dispersion correction : off ************************* Pseudopotential Parameters ************************** pseudopotential representation : reciprocal space <beta|phi> representation : reciprocal space **************************** Basis Set Parameters ***************************** plane wave basis set cut-off : 280.0000 eV size of standard grid : 1.5000 size of fine gmax : 12.8590 1/A largest prime factor in FFT : 5 finite basis set correction : automatic number of sample energies : 3 sample spacing : 5.0000 eV **************************** Electronic Parameters **************************** number of electrons : 310.0 net charge of system : 0.000 net spin of system : 10.00 number of up spins : 160.0 number of down spins : 150.0 treating system as spin-polarized number of bands : 193 ********************* Electronic Minimization Parameters ********************** Method: Treating system as metallic with density mixing treatment of electrons, and number of SD steps : 1 and number of CG steps : 4 total energy / atom convergence tol. : 0.1000E-04 eV eigen-energy convergence tolerance : 0.1000E-05 eV max force / atom convergence tol. : ignored convergence tolerance window : 3 cycles max. number of SCF cycles : 100 number of fixed-spin iterations : 6 smearing scheme : Gaussian smearing width : 0.1000 eV Fermi energy convergence tolerance : 0.1000E-06 eV periodic dipole correction : NONE ************************** Density Mixing Parameters ************************** density-mixing scheme : Pulay max. length of mixing history : 20 charge density mixing amplitude : 0.5000 spin density mixing amplitude : 2.000 cut-off energy for mixing : 280.0 eV charge density mixing g-vector : 1.500 1/A spin density mixing g-vector : 1.500 1/A *********************** Population Analysis Parameters ************************ Population analysis with cutoff : 3.000 A ********************** Geometry Optimization Parameters *********************** optimization method : BFGS variable cell method : fixed basis quality max. number of steps : 100 estimated bulk modulus : 500.0 GPa estimated <frequency> : 1668. cm-1 geom line minimiser : on with line minimiser tolerance : 0.4000 with spin fully able to relax for all steps total energy convergence tolerance : 0.5000E-04 eV/atom max ionic |force| tolerance : 0.1000 eV/A max ionic |displacement| tolerance : 0.5000E-02 A max |stress component| tolerance : 0.2000 GPa convergence tolerance window : 2 steps backup results every : 5 steps 4.报错信息： 我试过两种，一种就直接失败了，不收敛： *Warning* max. SCF cycles performed but system has not reached the groundstate. Current total energy, E = -29833.17159871 eV Current free energy (E-TS) = -29833.31934436 eV (energies not corrected for finite basis set) NB est. 0K energy (E-0.5TS) = -29833.24547154 eV **************************************************************************** Warning: electronic minimisation did not converge when finding ground state. **************************************************************************** Writing model to Fe_25.check Error in geom_get_forces - electronic_minimisation of current_cell failed Current trace stack: geom_get_forces geom_BFGS geometry_optimise castep Error in geom_get_forces - electronic_minimisation of current_cell failed Current trace stack: geom_get_forces geom_BFGS geometry_optimise castep 还有一种是几何优化4项，3个no1个也yes： +-----------+-----------------+-----------------+------------+-----+ <-- BFGS | Parameter | value | tolerance | units | OK? | <-- BFGS +-----------+-----------------+-----------------+------------+-----+ <-- BFGS | dE/ion | 8.339837E-002 | 5.000000E-005 | eV | No | <-- BFGS | |F|max | 1.288961E-001 | 1.000000E-001 | eV/A | No | <-- BFGS | |dR|max | 6.082554E-004 | 5.000000E-003 | A | Yes | <-- BFGS | Smax | 4.065663E+000 | 2.000000E-001 | GPa | No | <-- BFGS +-----------+-----------------+-----------------+------------+-----+ <-- BFGS BFGS : WARNING - Geometry optimization failed to converge after 100 steps BFGS : Final Enthalpy = -2.98380067E+004 eV BFGS : Final <frequency> = 7075.84270 cm-1 BFGS : Final bulk modulus unchanged from initial value ********************************************************** *** There were at least 1 warnings during this run *** *** => please check the whole of this file carefully! *** ********************************************************** |
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