# CCL:G: Difference Between Two Different Types of Failure to Converge

• From: "Abrash, Samuel" <sabrash(a)richmond.edu>
• Subject: CCL:G: Difference Between Two Different Types of Failure to Converge
• Date: Tue, 17 Jan 2006 16:08:17 -0500

``` Sent to CCL by: "Abrash, Samuel" [sabrash(a)richmond.edu]
Hi CCL Folks!
I need some help understanding the difference between two different
types of
termination because of failure to converge.
The first is the one I understand best.  In this case, the optimization
is set to
run a maxiumum number of Berny cycles, and after the full number of allowed
cycles
(in my case 100), one or more of the four convergence criteria is unfulfilled.
For
this type of problem I have a pretty good idea of what to do. 1) Look at the
output
file to see if the structures are physically reasonable and moving toward
convergence.  2a)  If yes, just continue the job  2b) If no, try a different set
of
initial conditions, or modify the theory as needed. (Lots of options depending
on
the situation.)
The second type of case is one where the failure to converge comes not
on the final
Berny cycle but on an early one.
Here are the input file and the portion of the output file indicating
the type of
convergence failure for one of these jobs:
Input:
%chk=/home/saabrash/C2H2TCalcs/cyclopropanetrismethylene+_1.chk
%mem=12mw
# UHF/3-21G OPT=(calcall, maxcycle=100) SCF=qc
cyclopropanetrismethylene cation PBEPBE/aug-cc-pVDZ init geom arguslab
low symm
1  2
C       -0.317858       1.277419        0.119868
C       -0.287771       2.616099        0.000000
C       0.643137        0.346751        0.202150
C       2.040557        0.274690        0.000000
C       -0.694918       -0.054486       -0.097643
C       -1.569659       -1.098761       0.000000
H       0.676927        3.142444        -0.048150
H       -1.227851       3.185096        -0.049928
H       2.597937        1.169980        -0.312708
H       2.570431        -0.676665       0.155427
H       -1.248715       -2.043628       0.462842
H       -2.595146       -0.994986       -0.384198
%chk=/home/saabrash/C2H2TCalcs/cyclopropanetrismethylene+_1.chk
%mem=12mw
%chk=/home/saabrash/C2H2TCalcs/cyclopropanetrismethylene+_1.chk
%mem=15mw
geom=allcheck
%chk=/home/saabrash/C2H2TCalcs/cyclopropanetrismethylene+_1.chk
%mem=15mw
# UPBEPBE/aug-cc-pVDZ Opt=(rcfc, maxcycle=100) geom=allcheck
%chk=/home/saabrash/C2H2TCalcs/cyclopropanetrismethylene+_1.chk
%mem=15mw
The job runs successfully for the two UHF jobs.  Then on the second
Berny cycle of
the UPBEPBE/aug-cc-pVDZ there is a failure to converge.  The full output for the
second cycle is:
Berny optimization.
Internal  Forces:  Max     0.004030705 RMS     0.001018805
Search for a local minimum.
Step number   2 out of a maximum of 100
All quantities printed in internal units (Hartrees-Bohrs-Radians)
Update second derivatives using D2CorX and points  1  2
Trust test= 9.84D-01 RLast= 1.76D-01 DXMaxT set to 4.24D-01
Eigenvalues ---    0.00363   0.00457   0.00637   0.00716   0.00970
Eigenvalues ---    0.01542   0.03555   0.03561   0.03740   0.08693
Eigenvalues ---    0.09833   0.09905   0.11931   0.11966   0.12082
Eigenvalues ---    0.15236   0.15836   0.16085   0.33837   0.33897
Eigenvalues ---    0.37796   0.40451   0.40476   0.40507   0.40534
Eigenvalues ---    0.40557   0.42351   0.42412   0.47209   0.49435
Eigenvalues --- 1000.000001000.000001000.000001000.000001000.00000
Eigenvalues --- 1000.000001000.000001000.000001000.00001000.00000
Eigenvalues --- 1000.000001000.00000
RFO step:  Lambda=-9.49095729D-05.
Quartic linear search produced a step of  0.03710.
Iteration  1 RMS(Cart)=  0.00420970 RMS(Int)=  0.00000257
Iteration  2 RMS(Cart)=  0.00000342 RMS(Int)=  0.00000178
Iteration  3 RMS(Cart)=  0.00000000 RMS(Int)=  0.00000178
Variable       Old X    -DE/DX   Delta X   Delta X   Delta X     New X
R1        2.63333   0.00137  -0.00069   0.00371   0.00302   2.63635
R2        2.65714   0.00191   0.00154   0.00325   0.00479   2.66192
R3        2.72881   0.00062   0.00278  -0.00162   0.00116   2.72997
R4        2.07080   0.00174   0.00171   0.00319   0.00491   2.07571
R5        2.07026   0.00186   0.00172   0.00341   0.00513   2.07539
R6        2.63334   0.00137  -0.00069   0.00370   0.00301   2.63635
R7        2.72882   0.00062   0.00278  -0.00163   0.00116   2.72997
R8        2.07080   0.00174   0.00171   0.00319   0.00491   2.07571
R9        2.07026   0.00186   0.00172   0.00341   0.00513   2.07539
R10        2.55046   0.00403  -0.00217   0.01109   0.00891   2.55937
R11        2.06913   0.00170   0.00168   0.00298   0.00466   2.07379
R12        2.06913   0.00170   0.00168   0.00298   0.00466   2.07379
A1        2.56260   0.00008  -0.00069   0.00018  -0.00051   2.56210
A2        2.65828   0.00019   0.00043   0.00084   0.00127   2.65956
A3        2.10190  -0.00016   0.00002  -0.00138  -0.00136   2.10054
A4        2.10755   0.00022   0.00019   0.00124   0.00143   2.10897
A5        2.07374  -0.00006  -0.00021   0.00014  -0.00007   2.07367
A6        2.56260   0.00008  -0.00069   0.00018  -0.00050   2.56210
A7        2.65829   0.00019   0.00043   0.00083   0.00127   2.65956
A8        2.10189  -0.00016   0.00002  -0.00138  -0.00136   2.10054
A9        2.10755   0.00022   0.00019   0.00124   0.00143   2.10898
A10        2.07374  -0.00006  -0.00021   0.00014  -0.00007   2.07367
A11        2.63309  -0.00027   0.00025  -0.00101  -0.00077   2.63233
A12        2.63309  -0.00027   0.00025  -0.00102  -0.00077   2.63233
A13        2.10983   0.00000   0.00017  -0.00111  -0.00094   2.10889
A14        2.10983   0.00000   0.00017  -0.00111  -0.00094   2.10889
A15        2.06352   0.00001  -0.00034   0.00223   0.00189   2.06541
D1        0.00000   0.00000   0.00000   0.00001   0.00001   0.00001
D2        3.14159   0.00000   0.00000   0.00001   0.00001  -3.14159
D3       -3.14158   0.00000   0.00000   0.00001   0.00001  -3.14157
D4        0.00001   0.00000   0.00000   0.00001   0.00001   0.00002
D5        0.00001   0.00000   0.00000   0.00000   0.00000   0.00001
D6       -0.00001   0.00000   0.00000   0.00000   0.00000  -0.00001
D7        0.00000   0.00000   0.00000   0.00001   0.00001   0.00001
D8       -3.14159   0.00000   0.00000   0.00000   0.00000  -3.14158
D9       -3.14159   0.00000   0.00000   0.00001   0.00001  -3.14158
D10        0.00001   0.00000   0.00000   0.00001   0.00001   0.00002
D11        0.00000   0.00000   0.00000   0.00000   0.00000   0.00000
D12        3.14158   0.00000   0.00000   0.00002   0.00002  -3.14159
D13       -0.00002   0.00000   0.00000   0.00002   0.00002   0.00001
D14       -0.00002   0.00000   0.00000   0.00002   0.00002   0.00000
D15        3.14158   0.00000   0.00000   0.00002   0.00002   3.14159
Item               Value     Threshold  Converged?
Maximum Force            0.004031     0.000450     NO
RMS     Force            0.001019     0.000300     NO
Maximum Displacement     0.010397     0.001800     NO
RMS     Displacement     0.004210     0.001200     NO
Predicted change in Energy=-5.395842D-05

Input orientation:
---------------------------------------------------------------------
Center     Atomic     Atomic              Coordinates (Angstroms)
Number     Number      Type              X           Y           Z
---------------------------------------------------------------------
1          6             0       -0.237228    0.763057   -0.028393
2          6             0       -0.534705    2.125159   -0.078167
3          6             0        0.767704   -0.223151    0.013368
4          6             0        2.135799   -0.495591    0.032816
5          6             0       -0.618580   -0.629581    0.017521
6          6             0       -1.567594   -1.595472    0.044403
7          1             0        0.272986    2.869305   -0.098334
8          1             0       -1.576033    2.473585   -0.097891
9          1             0        2.865548    0.325046    0.009436
10          1             0        2.503343   -1.529786    0.071622
11          1             0       -1.289422   -2.656312    0.083505
12          1             0       -2.633950   -1.336829    0.027627
---------------------------------------------------------------------
Distance matrix (angstroms):
1          2          3          4          5
1  C    0.000000
2  C    1.395096   0.00000     0        1.148793   -1.871634
0.000001
5          6             0       -0.876500   -0.000009   -0.000001
6          6             0       -2.230861   -0.000022    0.000000
7          1             0        2.245813    1.817045   -0.000012
8          1             0        0.667953    2.859072    0.000009
9          1             0        2.245853   -1.816996    0.000015
10          1             0        0.668017   -2.859059   -0.000011
11          1             0       -2.793270   -0.942353    0.000002
12          1             0       -2.793287    0.942299    0.000000
---------------------------------------------------------------------
Rotational constants (GHZ):      4.1801422      3.8590844
2.0066012
Standard basis: Aug-CC-pVDZ (5D, 7F)
There are   192 symmetry adapted basis functions of A   symmetry.
Integral buffers will be    262144 words long.
Raffenetti 2 integral format.
Two-electron integral symmetry is turned on.
192 basis functions,   324 primitive gaussians,   204 cartesian basis
functio
ns
21 alpha electrons       20 beta electrons
nuclear repulsion energy       186.6386459511 Hartrees.
NAtoms=   12 NActive=   12 NUniq=   12 SFac= 1.00Dá?? NAtFMM=   60
Big=F
One-electron integrals computed using PRISM.
NBasis=   192 RedAO= T  NBF=   192
NBsUse=   192 1.00D-06 NBFU=   192
Initial guess orbital symmetries:
Alpha Orbitals:
Occupied  (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A)
(A) (A) (A) (A) (A) (A) (A) (A) (A)
Virtual   (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A)
(A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A)
<S**2> of initial guess= 0.8964
Requested convergence on RMS density matrix=1.00D-08 within 128 cycles.
Requested convergence on MAX density matrix=1.00D-06.
Requested convergence on             energy=1.00D-06.
No special actions if energy rises.
EnCoef did     4 forward-backward iterations
EnCoef did     5 forward-backward iterations
EnCoef did     2 forward-backward iterations
EnCoef did    85 forward-backward iterations
Rare condition: small coef for last iteration: -0.666D-15
EnCoef did     5 forward-backward iterations
Rare condition: small coef for last iteration:  0.222D-15
EnCoef did     6 forward-backward iterations
Rare condition: small coef for last iteration:  0.000Dá??
EnCoef did     7 forward-backward iterations
Rare condition: small coef for last iteration:  0.000Dá??
Restarting incremental Fock formation.
EnCoef did   100 forward-backward iterations
Matrix for removal  1 Erem= -223.464925078448     Crem= 0.000Dá??
EnCoef did   100 forward-backward iterations
Rare condition: small coef for last iteration: -0.432D-15
Matrix for removal  1 Erem= -225.612036927259     Crem= 0.000Dá??
EnCoef did    48 forward-backward iterations
Matrix for removal  2 Erem= -230.056216034563     Crem= 0.000Dá??
Rare condition: small coef for last iteration:  0.444D-15
Matrix for removal  1 Erem= -230.957780613922     Crem= 0.000Dá??
EnCoef did    48 forward-backward iterations
Matrix for removal  3 Erem= -231.371944287973     Crem= 0.000Dá??
Rare condition: small coef for last iteration: -0.222D-15
Matrix for removal  6 Erem= -231.413745729862     Crem= 0.000Dá??
EnCoef did     6 forward-backward iterations
Matrix for removal  1 Erem= -231.416133716719     Crem= 0.000Dá??
Rare condition: small coef for last iteration:  0.000Dá??
Matrix for removal 13 Erem= -231.418900867161     Crem= 0.000Dá??
EnCoef did    59 forward-backward iterations
Matrix for removal 18 Erem= -231.419070999074     Crem= 0.000Dá??
Rare condition: small coef for last iteration: -0.444D-15
Matrix for removal 11 Erem= -231.419112348980     Crem= 0.000Dá??
EnCoef did   100 forward-backward iterations
Matrix for removal 18 Erem= -231.419148641413     Crem= 0.000Dá??
EnCoef did   100 forward-backward iterations
Rare condition: small coef for last iteration:  0.000Dá??
Matrix for removal 19 Erem= -231.418778276146     Crem= 0.000Dá??
EnCoef did   100 forward-backward iterations
Matrix for removal  9 Erem= -231.419169067006     Crem= 0.000Dá??
EnCoef did   100 forward-backward iterations
Rare condition: small coef for last iteration:  0.554D-15
Matrix for removal 19 Erem= -231.418942288017     Crem= 0.000Dá??
EnCoef did     6 forward-backward iterations
Matrix for removal 14 Erem= -231.419290263368     Crem= 0.000Dá??
Rare condition: small coef for last iteration:  0.000Dá??
Matrix for removal 19 Erem= -231.419107556261     Crem= 0.000Dá??
EnCoef did     6 forward-backward iterations
Matrix for removal 11 Erem= -231.420445394300     Crem= 0.000Dá??
Rare condition: small coef for last iteration: -0.222D-15
Matrix for removal 19 Erem= -231.419071776551     Crem= 0.000Dá??
EnCoef did     6 forward-backward iterations
Matrix for removal 12 Erem= -231.420604168141     Crem= 0.000Dá??
Rare condition: small coef for last iteration: -0.222D-15
Matrix for removal 19 Erem= -231.419149178448     Crem= 0.000Dá??
Restarting incremental Fock formation.
EnCoef did   100 forward-backward iterations
Matrix for removal 13 Erem= -231.420647898230     Crem= 0.000Dá??
EnCoef did   100 forward-backward iterations
Rare condition: small coef for last iteration: -0.111D-14
Matrix for removal 19 Erem= -231.418949995443     Crem= 0.000Dá??
EnCoef did     6 forward-backward iterations
Matrix for removal 17 Erem= -231.420648694361     Crem= 0.000Dá??
Rare condition: small coef for last iteration:  0.111D-15
Matrix for removal 19 Erem= -231.419096135031     Crem= 0.000Dá??
EnCoef did     6 forward-backward iterations
Matrix for removal  9 Erem= -231.420657719207     Crem= 0.000Dá??
Rare condition: small coef for last iteration:  0.000Dá??
Matrix for removal 19 Erem= -231.419104154891     Crem= 0.000Dá??
EnCoef did     6 forward-backward iterations
Matrix for removal 14 Erem= -231.420671893769     Crem= 0.000Dá??
Rare condition: small coef for last iteration:  0.000Dá??
Matrix for removal 19 Erem= -231.419081387961     Crem= 0.000Dá??
EnCoef did     6 forward-backward iterations
Matrix for removal 19 Erem= -231.420658305176     Crem= 0.000Dá??
Rare condition: small coef for last iteration:  0.111D-15
Matrix for removal 19 Erem= -231.419145661317     Crem= 0.000Dá??
EnCoef did   100 forward-backward iterations
Matrix for removal 17 Erem= -231.420673187415     Crem= 0.000Dá??
EnCoef did   100 forward-backward iterations
Rare condition: small coef for last iteration: -0.444D-15
Matrix for removal 19 Erem= -231.418960715007     Crem= 0.000Dá??
EnCoef did   100 forward-backward iterations
Matrix for removal 16 Erem= -231.420675973150     Crem= 0.000Dá??
EnCoef did   100 forward-backward iterations
Rare condition: small coef for last iteration: -0.444D-15
Matrix for removal 19 Erem= -231.419021266252     Crem= 0.000Dá??
EnCoef did    14 forward-backward iterations
Matrix for removal 16 Erem= -231.420681296646     Crem= 0.000Dá??
Rare condition: small coef for last iteration: -0.444D-15
Matrix for removal 19 Erem= -231.419335961191     Crem= 0.000Dá??
EnCoef did   100 forward-backward iterations
Matrix for removal 18 Erem= -231.420587572061     Crem= 0.000Dá??
EnCoef did   100 forward-backward iterations
Rare condition: small coef for last iteration: -0.440D-15
Matrix for removal 19 Erem= -231.418544675637     Crem= 0.000Dá??
EnCoef did    14 forward-backward iterations
Matrix for removal 11 Erem= -231.420684293649     Crem= 0.000Dá??
Rare condition: small coef for last iteration:  0.000Dá??
Matrix for removal 19 Erem= -231.419477236327     Crem= 0.000Dá??
Restarting incremental Fock formation.
EnCoef did   100 forward-backward iterations
Matrix for removal 18 Erem= -231.420534345081     Crem= 0.000Dá??
EnCoef did   100 forward-backward iterations
Rare condition: small coef for last iteration: -0.442D-15
Matrix for removal 19 Erem= -231.418796677540     Crem= 0.000Dá??
EnCoef did     6 forward-backward iterations
Matrix for removal 10 Erem= -231.419651241752     Crem= 0.000Dá??
Rare condition: small coef for last iteration:  0.111D-15
Matrix for removal 19 Erem= -231.419280599829     Crem= 0.000Dá??
EnCoef did   100 forward-backward iterations
Matrix for removal 18 Erem= -231.420608902185     Crem= 0.000Dá??
EnCoef did   100 forward-backward iterations
Rare condition: small coef for last iteration:  0.221D-15
Matrix for removal 19 Erem= -231.418906193179     Crem= 0.000Dá??
EnCoef did     6 forward-backward iterations
Matrix for removal 19 Erem= -231.420586795007     Crem= 0.000Dá??
Rare condition: small coef for last iteration: -0.222D-15
Matrix for removal 19 Erem= -231.419285531894     Crem= 0.000Dá??
EnCoef did   100 forward-backward iterations
Matrix for removal 12 Erem= -231.420684711108     Crem= 0.000Dá??
EnCoef did   100 forward-backward iterations
Rare condition: small coef for last iteration:  0.221D-15
Matrix for removal 19 Erem= -231.418892731624     Crem= 0.000Dá??
EnCoef did     6 forward-backward iterations
Matrix for removal 19 Erem= -231.420585363376     Crem= 0.000Dá??
Rare condition: small coef for last iteration:  0.000Dá??
Matrix for removal 19 Erem= -231.419289049853     Crem= 0.000Dá??
EnCoef did   100 forward-backward iterations
Matrix for removal 14 Erem= -231.420702235767     Crem= 0.000Dá??
EnCoef did   100 forward-backward iterations
Rare condition: small coef for last iteration:  0.331D-15
Matrix for removal 19 Erem= -231.418882803565     Crem= 0.000Dá??
EnCoef did     6 forward-backward iterations
Matrix for removal 19 Erem= -231.420581194769     Crem= 0.000Dá??
Rare condition: small coef for last iteration: -0.222D-15
Matrix for removal 19 Erem= -231.419299060760     Crem= 0.000Dá??
EnCoef did   100 forward-backward iterations
Matrix for removal 13 Erem= -231.420723664654     Crem= 0.000Dá??
EnCoef did   100 forward-backward iterations
Rare condition: small coef for last iteration: -0.441D-15
Matrix for removal 19 Erem= -231.418855077350     Crem= 0.000Dá??
EnCoef did    14 forward-backward iterations
Matrix for removal 12 Erem= -231.420727388183     Crem= 0.000Dá??
Rare condition: small coef for last iteration: -0.222D-15
Matrix for removal 19 Erem= -231.419324576409     Crem= 0.000Dá??
Restarting incremental Fock formation.
EnCoef did   100 forward-backward iterations
Matrix for removal 18 Erem= -231.420570563941     Crem= 0.000Dá??
EnCoef did   100 forward-backward iterations
Rare condition: small coef for last iteration:  0.110D-15
Matrix for removal 19 Erem= -231.418780647653     Crem= 0.000Dá??
EnCoef did    14 forward-backward iterations
Matrix for removal 11 Erem= -231.420730549360     Crem= 0.000Dá??
Rare condition: small coef for last iteration:  0.000Dá??
Matrix for removal 19 Erem= -231.419384341437     Crem= 0.000Dá??
EnCoef did   100 forward-backward iterations
Matrix for removal 18 Erem= -231.420545387770     Crem= 0.000Dá??
EnCoef did   100 forward-backward iterations
Rare condition: small coef for last iteration: -0.665D-15
Matrix for removal 19 Erem= -231.419018218195     Crem= 0.000Dá??
EnCoef did    14 forward-backward iterations
Matrix for removal 18 Erem= -231.420693067494     Crem= 0.000Dá??
Rare condition: small coef for last iteration:  0.444D-15
Matrix for removal 19 Erem= -231.419466794992     Crem= 0.000Dá??
EnCoef did   100 forward-backward iterations
Matrix for removal 18 Erem= -231.420508813558     Crem= 0.000Dá??
EnCoef did   100 forward-backward iterations
Rare condition: small coef for last iteration: -0.665D-15
Matrix for removal 19 Erem= -231.419030539317     Crem= 0.000Dá??
EnCoef did    14 forward-backward iterations
Matrix for removal 18 Erem= -231.420688269172     Crem= 0.000Dá??
Rare condition: small coef for last iteration:  0.777D-15
Matrix for removal 19 Erem= -231.419448841266     Crem= 0.000Dá??
EnCoef did   100 forward-backward iterations
Matrix for removal 18 Erem= -231.420516657136     Crem= 0.000Dá??
EnCoef did   100 forward-backward iterations
Rare condition: small coef for last iteration:  0.440D-15
Matrix for removal 19 Erem= -231.418503747344     Crem= 0.000Dá??
EnCoef did    15 forward-backward iterations
Matrix for removal 13 Erem= -231.420736420738     Crem= 0.000Dá??
Rare condition: small coef for last iteration:  0.111D-15
Matrix for removal 19 Erem= -231.419515644416     Crem= 0.000Dá??
EnCoef did   100 forward-backward iterations
Matrix for removal 18 Erem= -231.420488445027     Crem= 0.000Dá??
EnCoef did   100 forward-backward iterations
Rare condition: small coef for last iteration: -0.220D-15
Matrix for removal 19 Erem= -231.418673619125     Crem= 0.000Dá??
EnCoef did    14 forward-backward iterations
Matrix for removal  9 Erem= -231.420739298607     Crem= 0.000Dá??
Rare condition: small coef for last iteration:  0.222D-15
Matrix for removal 18 Erem= -231.420515847041     Crem= 0.000Dá??
Restarting incremental Fock formation.
EnCoef did   100 forward-backward iterations
Matrix for removal 18 Erem= -231.419453081651     Crem= 0.000Dá??
EnCoef did   100 forward-backward iterations
Rare condition: small coef for last iteration:  0.144D-14
Matrix for removal 19 Erem= -231.419131280349     Crem= 0.000Dá??
EnCoef did   100 forward-backward iterations
Matrix for removal 18 Erem= -231.420653956973     Crem= 0.000Dá??
EnCoef did   100 forward-backward iterations
Rare condition: small coef for last iteration:  0.222D-15
Matrix for removal 19 Erem= -231.419031179958     Crem= 0.000Dá??
EnCoef did    14 forward-backward iterations
Matrix for removal 18 Erem= -231.420688123736     Crem= 0.000Dá??
Rare condition: small coef for last iteration: -0.666D-15
Matrix for removal 18 Erem= -231.420517077761     Crem= 0.000Dá??
EnCoef did   100 forward-backward iterations
Matrix for removal 18 Erem= -231.419447848080     Crem= 0.000Dá??
EnCoef did   100 forward-backward iterations
Rare condition: small coef for last iteration: -0.666D-15
Matrix for removal 19 Erem= -231.419123693065     Crem= 0.000Dá??
EnCoef did   100 forward-backward iterations
Matrix for removal 18 Erem= -231.420655788332     Crem= 0.000Dá??
EnCoef did   100 forward-backward iterations
Rare condition: small coef for last iteration:  0.111D-15
Matrix for removal 19 Erem= -231.419006604895     Crem= 0.000Dá??
EnCoef did    14 forward-backward iterations
Matrix for removal 12 Erem= -231.420741474519     Crem= 0.000Dá??
Rare condition: small coef for last iteration: -0.222D-15
Matrix for removal 19 Erem= -231.419483006932     Crem= 0.000Dá??
EnCoef did   100 forward-backward iterations
Matrix for removal 18 Erem= -231.420501705978     Crem= 0.000Dá??
EnCoef did   100 forward-backward iterations
Rare condition: small coef for last iteration:  0.221D-15
Matrix for removal 19 Erem= -231.418891457091     Crem= 0.000Dá??
EnCoef did     6 forward-backward iterations
Matrix for removal 19 Erem= -231.420584815358     Crem= 0.000Dá??
Rare condition: small coef for last iteration: -0.222D-15
Matrix for removal 19 Erem= -231.419290379712     Crem= 0.000Dá??
EnCoef did   100 forward-backward iterations
Matrix for removal 17 Erem= -231.420697653495     Crem= 0.000Dá??
EnCoef did   100 forward-backward iterations
Rare condition: small coef for last iteration: -0.662D-15
Matrix for removal 19 Erem= -231.418878558166     Crem= 0.000Dá??
EnCoef did     6 forward-backward iterations
Matrix for removal 19 Erem= -231.420579763623     Crem= 0.000Dá??
Rare condition: small coef for last iteration:  0.000Dá??
Matrix for removal 19 Erem= -231.419302558715     Crem= 0.000Dá??
Restarting incremental Fock formation.
EnCoef did   100 forward-backward iterations
Matrix for removal 17 Erem= -231.420741463049     Crem= 0.000Dá??
EnCoef did   100 forward-backward iterations
Rare condition: small coef for last iteration:  0.000Dá??
Matrix for removal 19 Erem= -231.418842382202     Crem= 0.000Dá??
EnCoef did    14 forward-backward iterations
Matrix for removal 12 Erem= -231.420745177864     Crem= 0.000Dá??
Rare condition: small coef for last iteration: -0.111D-14
Matrix for removal 19 Erem= -231.419335069289     Crem= 0.000Dá??
EnCoef did   100 forward-backward iterations
Matrix for removal 18 Erem= -231.420566191137     Crem= 0.000Dá??
EnCoef did   100 forward-backward iterations
Rare condition: small coef for last iteration: -0.220D-15
Matrix for removal 19 Erem= -231.418736422553     Crem= 0.000Dá??
EnCoef did    14 forward-backward iterations
Matrix for removal 16 Erem= -231.420746777662     Crem= 0.000Dá??
Rare condition: small coef for last iteration: -0.444D-15
Matrix for removal 19 Erem= -231.419414870194     Crem= 0.000Dá??
EnCoef did   100 forward-backward iterations
Matrix for removal 18 Erem= -231.420532350979     Crem= 0.000Dá??
>>>>>>>>>> Convergence criterion not met.
SCF Done:  E(UPBE-PBE) =  -231.418804396     A.U. after  129 cycles
Convg  =    0.3553D-03             -V/T =  2.0061
S**2   =   0.7575
Annihilation of the first spin contaminant:
S**2 before annihilation     0.7575,   after     0.7500
Convergence failure -- run terminated.
Error termination via Lnk1e in /usr/global/g03/l502.exe at Thu Dec 29
17:09:52
2005.
Job cpu time:  0 days  4 hours  5 minutes  9.7 seconds.
File lengths (MBytes):  RWF=     51 Int=      0 D2E=      0 Chk=      7
Scr=
1
So I have two questions:
1)  Is this a failure in geometric convergence, convergence of the
integrals or
what?  I really don't understand WHAT it is that isn't converging.
2) What types of remedies are available when this occurs?  If you saw
this in one
of your jobs what would you do next?
Thanks, and once again I appreciate your help.
Best,
Sam
```