<div dir="ltr"><div><div><div><div><div><div>Hi everyone,<br><br></div>  I tried to compare molpro and mrcc full-ci/cc-pVDZ for a lithium atom and posted my question on mrcc forum.<br><br></div>The molpro convergence pattern is<br><br>  1   1    0.6  1.00000000    -7.43241988<br>                                           0.03 -0.00020840 -0.00020768<br>  2   1    0.6  0.00860636    -7.43263477<br>                                           0.05 -0.00000213 -0.00000210<br>  3   1    0.6  0.00085487    -7.43263690<br>                                           0.09 -0.00000004 -0.00000003<br>  4   1    0.6  0.00009565    -7.43263693<br>                                           0.11 -0.00000000 -0.00000000<br>  5   1    0.6  0.00001648    -7.43263693<br>                                           0.10 -0.00000000 -0.00000000<br>  6   1    0.6  0.00000299    -7.43263693<br>                                           0.12 -0.00000000 -0.00000000<br>  7   1    0.6  0.00000052    -7.43263693<br>                                           0.11 -0.00000000 -0.00000000<br>  8   1    0.6  0.00000010    -7.43263693<br><br></div>mrcc is <br> <br> Iteration  8  CI energy:    -7.43263751  Energy decrease:   0.0000E+00<br> ======================================================================<br> Norm of residual vector:     1.0477E-12      Convergence:   5.1862E-12<br> CPU time [min]:     0.012                   Wall time [min]:     0.002<br> <br> Iteration  9  CI energy:    -7.43263751  Energy decrease:   0.0000E+00<br> ======================================================================<br> Norm of residual vector:     4.7386E-14      Convergence:   2.1137E-13<br> CPU time [min]:     0.013                   Wall time [min]:     0.002<br> <br> Iteration 10  CI energy:    -7.43263751  Energy decrease:   0.0000E+00<br> ======================================================================<br> Norm of residual vector:     1.8060E-15      Convergence:   1.2633E-14<br> CPU time [min]:     0.014                   Wall time [min]:     0.002<br> <br> Iteration 11  CI energy:    -7.43263751  Energy decrease:   0.0000E+00<br><br><br></div>Though I was suggested to tighten molpro convergence threshold, my input:  <br>{fci;thr,1d-16;core,0}<br></div>and convergence pattern seems unable to reach mrcc value. Hence, I would like to ask in this mailing list, what is the actual reason for this discrepancy? i.e. <br>  -7.43263693<br>  -7.43263751 <br><br></div>Thank you<br><div><br><div><br></div></div></div>