Dear all,
I am currently running into a problem of the SCF convergence regarding to the orbital gradient. From the output:
Total Energy Delta E RMS |[F,P]|
@DF-UKS iter 1: -93947.62263282910862 -9.39476e+04 4.96184e-01 DIIS
@DF-UKS iter 2: -93083.06625863121008 8.64556e+02 3.15258e-01 DIIS/DAMP=30%
@DF-UKS iter 3: -93670.20860105322208 -5.87142e+02 1.65549e-01 DIIS/DAMP=30%
@DF-UKS iter 4: -94862.55785840435419 -1.19235e+03 1.28081e-01 DIIS/DAMP=30%
@DF-UKS iter 5: -94309.86640123746474 5.52691e+02 1.39700e-01 DIIS/DAMP=30%
@DF-UKS iter 6: -94644.76525786289130 -3.34899e+02 8.48098e-02 DIIS/DAMP=30%
@DF-UKS iter 7: -94858.76015601100517 -2.13995e+02 8.52922e-02 DIIS/DAMP=30%
@DF-UKS iter 8: -94798.61941630626097 6.01407e+01 7.48526e-02 DIIS/DAMP=30%
@DF-UKS iter 9: -94900.49050649242417 -1.01871e+02 7.96792e-02 DIIS/DAMP=30%
@DF-UKS iter 10: -94818.81550006117322 8.16750e+01 7.20902e-02 DIIS/DAMP=30%
@DF-UKS iter 11: -94778.41620374155173 4.03993e+01 8.31602e-02 DIIS/DAMP=30%
@DF-UKS iter 12: -94815.70220472227084 -3.72860e+01 8.78022e-02 DIIS/DAMP=30%
@DF-UKS iter 13: -94872.66261747252429 -5.69604e+01 7.40944e-02 DIIS/DAMP=30%
@DF-UKS iter 14: -94873.21119807503419 -5.48581e-01 8.10360e-02 DIIS/DAMP=30%
@DF-UKS iter 15: -94791.74027073250909 8.14709e+01 9.67722e-02 DIIS/DAMP=30%
@DF-UKS iter 16: -94946.80487266201817 -1.55065e+02 4.65549e-02 DIIS/DAMP=30%
@DF-UKS iter 17: -94725.75117995256733 2.21054e+02 8.42222e-02 DIIS/DAMP=30%
@DF-UKS iter 18: -94762.76879116657074 -3.70176e+01 8.41985e-02 DIIS/DAMP=30%
@DF-UKS iter 19: -94789.22667692959658 -2.64579e+01 8.49103e-02 DIIS/DAMP=30%
@DF-UKS iter 20: -94807.82568826185889 -1.85990e+01 7.74323e-02 DIIS/DAMP=30%
@DF-UKS iter 21: -94822.34396569037926 -1.45183e+01 7.77712e-02 DIIS/DAMP=30%
@DF-UKS iter 22: -94818.70148190246255 3.64248e+00 8.53658e-02 DIIS/DAMP=30%
@DF-UKS iter 23: -94802.57924583772547 1.61222e+01 8.75405e-02 DIIS/DAMP=30%
@DF-UKS iter 24: -94799.41612294694642 3.16312e+00 8.81203e-02 DIIS/DAMP=30%
@DF-UKS iter 25: -94798.67187531029049 7.44248e-01 8.82933e-02 DIIS/DAMP=30%
@DF-UKS iter 26: -94798.47921984079585 1.92655e-01 8.83463e-02 DIIS/DAMP=30%
@DF-UKS iter 27: -94798.42999715192127 4.92227e-02 8.83625e-02 DIIS/DAMP=30%
@DF-UKS iter 28: -94798.41773723006190 1.22599e-02 8.83674e-02 DIIS/DAMP=30%
@DF-UKS iter 29: -94798.41478065156844 2.95658e-03 8.83689e-02 DIIS/DAMP=30%
@DF-UKS iter 30: -94798.41410212684423 6.78525e-04 8.83694e-02 DIIS/DAMP=30%
@DF-UKS iter 31: -94798.41395896987524 1.43157e-04 8.83695e-02 DIIS/DAMP=30%
@DF-UKS iter 32: -94798.41393359792710 2.53719e-05 8.83695e-02 DIIS/DAMP=30%
@DF-UKS iter 33: -94798.41393112475635 2.47317e-06 8.83695e-02 DIIS/DAMP=30%
@DF-UKS iter 34: -94798.41393189138034 -7.66624e-07 8.83696e-02 DIIS/DAMP=30%
@DF-UKS iter 35: -94798.41393256612355 -6.74743e-07 8.83696e-02 DIIS/DAMP=30%
@DF-UKS iter 36: -94798.41393290000269 -3.33879e-07 8.83696e-02 DIIS/DAMP=30%
@DF-UKS iter 37: -94798.41393303919176 -1.39189e-07 8.83696e-02 DIIS/DAMP=30%
@DF-UKS iter 38: -94798.41393309258274 -5.33910e-08 8.83696e-02 DIIS/DAMP=30%
@DF-UKS iter 39: -94798.41393311202410 -1.94414e-08 8.83696e-02 DIIS/DAMP=30%
…
It is clear that the energy quickly converges but the orbital gradient becomes a constant as the iteration proceeds. Eventually, the “Failed to converge.” error message comes out.
I have tried some tricks as suggested in other posts, such as
#not work, just slow down the calculation
#set dft_spherical_points 590
#set dft_radial_points 99
set soscf true
set soscf_max_iter 35
set DIIS_MAX_VECS 10
set DAMPING_PERCENTAGE 30.0
set MAXITER 150
set guess core
(The trick of initial guess cannot be used since my molecule contains lanthanide elements. )
So how to help the orbital gradient converges? Any suggestion is deeply appreciated.
As a last resort, I probably will relax the convergence criteria by setting D_CONVERGENCE to 1e-2. I wonder how safe it is? It appears OK to me for numerical geometry optimization and frequency calculation. If so, how to switch on the numerical optimization and frequency calculation?
Many thanks for your help.
In the attached file, there is my input.
Best
test.txt (580 Bytes)