SCF failed to converge

Hi, I got a error message ¨ SCF failed to converge¨. Has anyone come across this error and how to solve it? Here is the input file:
$molecule
0 1
I 1.01740000 16.44210000 24.50580000
C 1.14650000 17.96940000 23.09310000
C 1.19680000 17.61200000 21.78550000
C 1.18260000 19.36610000 23.47650000
C 1.30670000 18.61940000 20.75940000
H 1.15960000 16.69380000 21.54450000
I 1.20110000 19.96120000 25.48530000
C 1.25460000 20.33990000 22.53040000
N 1.36740000 18.23600000 19.49540000
C 1.32910000 20.00540000 21.14690000
H 1.25530000 21.25250000 22.79430000
C 1.47970000 19.20830000 18.56790000
N 1.42470000 20.98520000 20.24500000
C 1.58060000 18.82590000 17.20710000
C 1.51720000 20.60640000 18.95640000
C 1.58450000 17.45570000 16.83520000
C 1.71530000 19.84590000 16.21820000
C 1.65200000 21.62640000 17.96730000
C 1.59990000 16.29810000 16.56640000
C 1.75300000 21.24400000 16.60650000
N 1.80790000 19.46720000 14.92940000
C 1.64800000 22.99660000 18.33920000
Si 1.75180000 14.48120000 16.29300000
N 1.86520000 22.21630000 15.67900000
C 1.90340000 20.44710000 14.02740000
C 1.63260000 24.15420000 18.60800000
C 3.43350000 13.99390000 17.02990000
C 1.72860000 14.15810000 14.43170000
C 0.34580000 13.70130000 17.28150000
C 1.92580000 21.83290000 14.41500000
C 1.97790000 20.11240000 12.64400000
Si 1.48070000 25.97120000 18.88150000
H 3.56330000 13.01570000 16.86860000
C 4.58480000 14.73340000 16.34680000
C 3.45090000 14.22040000 18.53780000
H 2.55650000 14.58690000 14.07010000
C 1.83940000 12.68340000 14.08380000
C 0.55470000 14.84600000 13.71930000
H 0.41610000 14.07280000 18.20730000
C 0.49020000 12.18050000 17.41800000
C -1.04250000 14.07360000 16.77820000
C 2.03560000 22.84030000 13.38900000
C 2.04990000 21.08610000 11.69810000
H 1.97730000 19.19960000 12.38020000
C -0.20090000 26.45840000 18.14450000
C 1.50390000 26.29420000 20.74270000
C 2.88670000 26.75100000 17.89290000
H 5.43120000 14.48570000 16.77410000
H 4.44720000 15.70010000 16.43030000
H 4.61340000 14.48830000 15.39850000
H 4.34430000 14.02070000 18.88780000
H 2.79400000 13.63140000 18.96410000
H 3.22580000 15.15450000 18.73040000
H 1.98360000 12.58540000 13.11940000
H 1.01200000 12.22460000 14.33870000
H 2.59440000 12.28930000 14.56870000
H 0.66130000 14.75290000 12.74950000
H 0.54040000 15.79690000 13.95650000
H -0.28670000 14.42750000 13.99710000
H -0.25220000 11.82870000 17.95230000
H 1.33920000 11.97130000 17.86050000
H 0.47560000 11.76980000 16.52830000
H -1.70440000 13.88480000 17.47570000
H -1.25180000 13.54780000 15.97810000
H -1.06460000 15.02810000 16.55680000
H 2.07300000 23.75840000 13.62990000
C 2.08600000 22.48280000 12.08140000
I 2.03160000 20.49110000 9.68930000
H -0.33070000 27.43670000 18.30580000
C -1.35220000 25.71870000 18.82760000
C -0.21830000 26.23190000 16.63660000
H 0.67610000 25.86560000 21.10430000
C 1.39310000 27.76890000 21.09060000
C 2.67790000 25.60610000 21.45520000
C 4.27510000 26.37880000 18.39620000
H 2.81650000 26.37950000 16.96710000
C 2.74240000 28.27180000 17.75640000
I 2.21530000 24.01020000 10.66860000
H -2.19870000 25.96660000 18.40030000
H -1.21460000 24.75220000 18.74410000
H -1.38090000 25.96400000 19.77590000
H -1.11170000 26.43160000 16.28680000
H 0.43860000 26.82090000 16.21030000
H 0.00680000 25.29790000 16.44400000
H 1.24890000 27.86690000 22.05510000
H 2.22050000 28.22790000 20.83570000
H 0.63830000 28.16300000 20.60570000
H 2.57130000 25.69940000 22.42490000
H 2.69210000 24.65540000 21.21790000
H 3.51930000 26.02480000 21.17730000
H 4.93700000 26.56760000 17.69870000
H 4.48440000 26.90460000 19.19630000
H 4.29720000 25.42430000 18.61760000
H 1.89350000 28.48100000 17.31390000
H 2.75690000 28.68250000 18.64610000
H 3.48470000 28.62360000 17.22210000
H -1.34470000 7.34270000 21.96060000
C -2.05380000 6.67100000 22.04060000
C -2.47150000 6.54920000 23.48840000
H -2.82440000 6.94360000 21.50000000
H -1.72140000 5.80560000 21.72270000
Si -1.05340000 5.93710000 24.58010000
H -2.71460000 7.46620000 23.80480000
C -3.70540000 5.68250000 23.63390000
C -0.83320000 4.16740000 24.14950000
C -1.57890000 5.99120000 26.39010000
C 0.57720000 6.80790000 24.24770000
H -4.42620000 6.04460000 23.07740000
H -3.98960000 5.67370000 24.57180000
H -3.49840000 4.76870000 23.34670000
C -0.79630000 3.01250000 23.84740000
H -2.50370000 5.61200000 26.42300000
C -1.68430000 7.41580000 26.92790000
C -0.72340000 5.10310000 27.29040000
H 0.57340000 6.63750000 23.26230000
C 0.52810000 8.30460000 24.12950000
C 1.77440000 6.13400000 24.49000000
C -0.79220000 1.63200000 23.48050000
H -2.06970000 7.39730000 27.82880000
H -2.25930000 7.94620000 26.33740000
H -0.79160000 7.81870000 26.96260000
H -1.06690000 5.14000000 28.20740000
H 0.20390000 5.42000000 27.27580000
H -0.75790000 4.17910000 26.96580000
H -0.07700000 8.55500000 23.40050000
H 1.42670000 8.64700000 23.94020000
H 0.20280000 8.68820000 24.97050000
H 1.62220000 5.16750000 24.43430000
H 2.10230000 6.36210000 25.38490000
H 2.43960000 6.39900000 23.82100000
C -0.67000000 1.25280000 22.11380000
C -0.96050000 0.63530000 24.46240000
C -0.68000000 -0.14140000 21.73440000
N -0.55560000 2.23300000 21.19730000
N -1.10090000 1.00900000 25.75310000
C -1.00180000 -0.76390000 24.07230000
C -0.82690000 -1.14790000 22.72430000
N -0.56610000 -0.51650000 20.44510000
C -0.48750000 1.84950000 19.92600000
C -1.25260000 0.04060000 26.64370000
N -1.17340000 -1.74370000 24.99070000
C -0.73590000 -2.52570000 22.39220000
C -0.48170000 0.46050000 19.54250000
C -0.42430000 2.85280000 18.90360000
C -1.36060000 0.36820000 28.03070000
C -1.29110000 -1.35120000 26.25470000
C -0.62490000 -3.71010000 22.20020000
C -0.42890000 0.12660000 18.15700000
C -0.39370000 2.49220000 17.60390000
H -0.40410000 3.77230000 19.14170000
H -1.37110000 1.27950000 28.29920000
C -1.44790000 -0.60610000 28.96510000
C -1.43730000 -2.35530000 27.27020000
Si -0.48290000 -5.53640000 22.08110000
H -0.41160000 -0.78540000 17.89220000
C -0.40310000 1.10480000 17.21150000
I -0.34530000 4.03580000 16.18600000
I -1.42140000 -0.01430000 30.97810000
C -1.50460000 -2.00160000 28.58120000
H -1.48730000 -3.27180000 27.02490000
C 1.31100000 -5.98680000 22.47590000
C -0.85750000 -5.99580000 20.29180000
C -1.75590000 -6.23100000 23.30010000
I -0.41390000 0.49990000 15.20500000
I -1.64200000 -3.53570000 29.99160000
H 1.42470000 -6.96330000 22.29270000
C 1.69700000 -5.74290000 23.93070000
C 2.27180000 -5.22560000 21.55030000
H -0.23670000 -5.45250000 19.72670000
C -0.56790000 -7.46340000 19.96010000
C -2.27540000 -5.58530000 19.88880000
H -2.64870000 -6.10400000 22.86780000
C -1.60640000 -7.73360000 23.52130000
C -1.82210000 -5.47610000 24.63760000
H 2.65690000 -5.90370000 24.04540000
H 1.19240000 -6.35210000 24.50920000
H 1.48990000 -4.81600000 24.17260000
H 3.19670000 -5.45320000 21.78120000
H 2.13550000 -4.26140000 21.65990000
H 2.09620000 -5.47680000 20.61940000
H -0.72900000 -7.62070000 19.00630000
H -1.15620000 -8.04040000 20.49030000
H 0.36710000 -7.66770000 20.17150000
H -2.41290000 -5.77670000 18.93760000
H -2.39580000 -4.62610000 20.04980000
H -2.92520000 -6.09000000 20.42100000
H -2.34310000 -8.05610000 24.08150000
H -0.75310000 -7.91470000 23.96770000
H -1.62730000 -8.19480000 22.65690000
H -2.60770000 -5.77360000 25.14210000
H -1.88930000 -4.51340000 24.46630000
H -1.01150000 -5.65960000 25.15670000
$end

!QSYS wt=96h

$rem
METHOD = PBE50
BASIS = USER1
ECP gen
ECP_FIT true
SCF_GUESS CORE
SCF_ALGORITHM RCA_DIIS
MAX_RCA_CYCLES 100
SYMMETRY = off
SYM_IGNORE = true
UNRESTRICTED = true
CDFTCI = true
CDFTCI_PRINT = 2
CDFT_THRESH = 7
mem_total = 120000
mem_static = 1000
threads 16
$end

$ecp
I 0
I-ECP 3 46
f potential
5
0 1.0715702 -0.0747621
1 44.1936028 -30.0811224
2 12.9367609 -75.3722721
2 3.1956412 -22.0563758
2 0.8589806 -1.6979585
s-f potential
5
0 127.9202670 2.9380036
1 78.6211465 41.2471267
2 36.5146237 287.8680095
2 9.9065681 114.3758506
2 1.9420086 37.6547714
p-f potential
5
0 13.0035304 2.2222630
1 76.0331404 39.4090831
2 24.1961684 177.4075002
2 6.4053433 77.9889462
2 1.5851786 25.7547641
d-f potential
5
0 40.4278108 7.0524360
1 28.9084375 33.3041635
2 15.6268936 186.9453875
2 4.1442856 71.9688361
2 0.9377235 9.3630657


$end

$cdft
0
1.0 1 96
0
1.0 1 96 S

1
1.0 1 96
1
1.0 1 96 S
$end

First guess, try THRESH=12 or 14. Q-Chem default is not appropriate for molecules of this size.

Note that it’s also better to use the </> button for formatted text, otherwise some of your input/output gets interpreted as special characters by this platform.

!QSYS wt=336:00:00
!qsys scratch 100g

$molecule
0 1
 I      3.97660000    5.22820000    6.91860000
 I      4.16030000    8.74720000    7.89810000
 Si     4.71110000    3.26720000   -1.29420000
 C      4.54380000    6.24180000   -0.75200000
 C      4.55910000    5.08410000   -1.02080000
 C      4.53980000    7.61200000   -0.38010000
 C      4.43890000    7.99440000    0.98070000
 N      4.32660000    7.02200000    1.90820000
 C      4.26600000    7.40550000    3.17220000
 C      4.15610000    6.39800000    4.19820000
 H      4.11880000    5.47980000    3.95730000
 C      4.10570000    6.75540000    5.50580000
 C      4.14180000    8.15220000    5.88920000
 C      4.21380000    9.12590000    4.94320000
 H      4.21450000   10.03850000    5.20700000
 C      4.28830000    8.79150000    3.55960000
 N      4.38390000    9.77120000    2.65780000
 C      4.47640000    9.39240000    1.36920000
 C      6.39270000    2.78000000   -0.55730000
 H      6.52250000    1.80170000   -0.71860000
 C      7.54400000    3.51940000   -1.24040000
 H      8.39040000    3.27170000   -0.81310000
 H      7.40640000    4.48620000   -1.15690000
 H      7.57270000    3.27440000   -2.18870000
 C      6.41010000    3.00640000    0.95060000
 H      7.30350000    2.80670000    1.30060000
 H      5.75320000    2.41740000    1.37690000
 H      6.18500000    3.94050000    1.14320000
 C      4.68780000    2.94420000   -3.15550000
 H      5.51570000    3.37290000   -3.51710000
 C      4.79870000    1.46950000   -3.50340000
 H      4.94290000    1.37140000   -4.46790000
 H      3.97120000    1.01070000   -3.24850000
 H      5.55360000    1.07530000   -3.01850000
 C      3.51390000    3.63210000   -3.86790000
 H      3.62050000    3.53900000   -4.83770000
 H      3.49970000    4.58290000   -3.63070000
 H      2.67250000    3.21360000   -3.59010000
 C      3.30510000    2.48730000   -0.30570000
 H      3.37530000    2.85880000    0.62010000
 C      3.44940000    0.96660000   -0.16920000
 H      2.70700000    0.61470000    0.36510000
 H      4.29840000    0.75730000    0.27330000
 H      3.43480000    0.55590000   -1.05890000
 C      1.91670000    2.85960000   -0.80900000
 H      1.25480000    2.67080000   -0.11150000
 H      1.70740000    2.33380000   -1.60910000
 H      1.89460000    3.81410000   -1.03040000
 I      5.17450000   12.79620000   -6.91860000
 I      4.99080000    9.27710000   -7.89790000
 Si     4.43990000   14.75720000    1.29420000
 C      4.60720000   11.78260000    0.75200000
 C      4.59180000   12.94020000    1.02080000
 C      4.61120000   10.41240000    0.38010000
 C      4.71220000   10.03000000   -0.98070000
 N      4.82440000   11.00240000   -1.90820000
 C      4.88500000   10.61890000   -3.17220000
 C      4.99480000   11.62640000   -4.19820000
 H      5.03220000   12.54440000   -3.95730000
 C      5.04530000   11.26880000   -5.50580000
 C      5.00910000    9.87210000   -5.88910000
 C      4.93710000    8.89850000   -4.94320000
 H      4.93650000    7.98570000   -5.20700000
 C      4.86270000    9.23320000   -3.55980000
 N      4.76710000    8.25320000   -2.65780000
 C      4.67450000    8.63190000   -1.36900000
 C      2.75830000   15.24440000    0.55730000
 H      2.62850000   16.22270000    0.71860000
 C      1.60700000   14.50480000    1.24040000
 H      0.76060000   14.75260000    0.81310000
 H      1.74460000   13.53820000    1.15690000
 H      1.57830000   14.75000000    2.18870000
 C      2.74090000   15.01800000   -0.95060000
 H      1.84750000   15.21760000   -1.30040000
 H      3.39780000   15.60700000   -1.37690000
 H      2.96600000   14.08390000   -1.14320000
 C      4.46320000   15.08020000    3.15550000
 H      3.63530000   14.65160000    3.51710000
 C      4.35230000   16.55490000    3.50340000
 H      4.20810000   16.65290000    4.46790000
 H      5.17980000   17.01390000    3.24850000
 H      3.59750000   16.94900000    3.01850000
 C      5.63710000   14.39210000    3.86790000
 H      5.53050000   14.48540000    4.83770000
 H      5.65130000   13.44150000    3.63070000
 H      6.47860000   14.81080000    3.59010000
 C      5.84590000   15.53710000    0.30570000
 H      5.77570000   15.16560000   -0.62010000
 C      5.70160000   17.05780000    0.16920000
 H      6.44390000   17.40960000   -0.36510000
 H      4.85270000   17.26700000   -0.27330000
 H      5.71620000   17.46850000    1.05890000
 C      7.23430000   15.16480000    0.80900000
 H      7.89620000   15.35360000    0.11150000
 H      7.44360000   15.69060000    1.60910000
 H      7.25640000   14.21030000    1.03040000
 I      4.00120000   30.06290000  -10.66860000
 I      4.18490000   33.58200000   -9.68910000
 Si     4.73570000   28.10200000  -18.88150000
 C      4.56840000   31.07660000  -18.33920000
 C      4.58380000   29.91890000  -18.60800000
 C      4.56440000   32.44670000  -17.96730000
 C      4.46350000   32.82910000  -16.60650000
 N      4.35120000   31.85680000  -15.67900000
 C      4.29060000   32.24020000  -14.41500000
 C      4.18070000   31.23280000  -13.38900000
 H      4.14340000   30.31460000  -13.62990000
 C      4.13030000   31.59020000  -12.08140000
 C      4.16650000   32.98690000  -11.69800000
 C      4.23850000   33.96070000  -12.64400000
 H      4.23910000   34.87330000  -12.38020000
 C      4.31290000   33.62620000  -14.02760000
 N      4.40850000   34.60600000  -14.92940000
 C      4.50110000   34.22720000  -16.21800000
 C      6.41730000   27.61470000  -18.14450000
 H      6.54710000   26.63650000  -18.30580000
 C      7.56860000   28.35420000  -18.82760000
 H      8.41500000   28.10650000  -18.40030000
 H      7.43100000   29.32090000  -18.74410000
 H      7.59730000   28.10910000  -19.77590000
 C      6.43470000   27.84120000  -16.63660000
 H      7.32810000   27.64150000  -16.28660000
 H      5.77780000   27.25220000  -16.21030000
 H      6.20960000   28.77530000  -16.44400000
 C      4.71240000   27.77890000  -20.74270000
 H      5.54030000   28.20770000  -21.10430000
 C      4.82330000   26.30420000  -21.09060000
 H      4.96750000   26.20620000  -22.05510000
 H      3.99580000   25.84540000  -20.83570000
 H      5.57820000   25.91010000  -20.60570000
 C      3.53850000   28.46690000  -21.45520000
 H      3.64510000   28.37370000  -22.42490000
 H      3.52430000   29.41770000  -21.21790000
 H      2.69720000   28.04830000  -21.17730000
 C      3.32970000   27.32210000  -17.89290000
 H      3.39990000   27.69360000  -16.96710000
 C      3.47400000   25.80130000  -17.75640000
 H      2.73160000   25.44950000  -17.22210000
 H      4.32300000   25.59210000  -17.31390000
 H      3.45940000   25.39070000  -18.64610000
 C      1.94130000   27.69440000  -18.39620000
 H      1.27940000   27.50550000  -17.69870000
 H      1.73200000   27.16850000  -19.19630000
 H      1.91920000   28.64890000  -18.61760000
 I      5.19910000   37.63100000  -24.50580000
 I      5.01540000   34.11190000  -25.48510000
 Si     4.46450000   39.59190000  -16.29300000
 C      4.63190000   36.61740000  -16.83520000
 C      4.61650000   37.77500000  -16.56640000
 C      4.63580000   35.24720000  -17.20710000
 C      4.73680000   34.86480000  -18.56790000
 N      4.84900000   35.83710000  -19.49540000
 C      4.90970000   35.45370000  -20.75940000
 C      5.01940000   36.46110000  -21.78550000
 H      5.05680000   37.37920000  -21.54450000
 C      5.06990000   36.10360000  -23.09310000
 C      5.03370000   34.70690000  -23.47630000
 C      4.96180000   33.73320000  -22.53040000
 H      4.96110000   32.82040000  -22.79430000
 C      4.88730000   34.06790000  -21.14700000
 N      4.79170000   33.08790000  -20.24500000
 C      4.69910000   33.46670000  -18.95620000
 C      2.78290000   40.07920000  -17.02990000
 H      2.65310000   41.05750000  -16.86860000
 C      1.63160000   39.33950000  -16.34680000
 H      0.78520000   39.58740000  -16.77410000
 H      1.76920000   38.37300000  -16.43030000
 H      1.60300000   39.58480000  -15.39850000
 C      2.76550000   39.85270000  -18.53780000
 H      1.87210000   40.05230000  -18.88760000
 H      3.42240000   40.44170000  -18.96410000
 H      2.99060000   38.91870000  -18.73040000
 C      4.48780000   39.91500000  -14.43170000
 H      3.65990000   39.48640000  -14.07010000
 C      4.37690000   41.38970000  -14.08380000
 H      4.23280000   41.48770000  -13.11940000
 H      5.20440000   41.84870000  -14.33870000
 H      3.62210000   41.78380000  -14.56870000
 C      5.66170000   39.22690000  -13.71930000
 H      5.55510000   39.32020000  -12.74950000
 H      5.67590000   38.27620000  -13.95650000
 H      6.50320000   39.64560000  -13.99710000
 C      5.87050000   40.37180000  -17.28150000
 H      5.80030000   40.00030000  -18.20730000
 C      5.72620000   41.89260000  -17.41800000
 H      6.46850000   42.24440000  -17.95230000
 H      4.87730000   42.10180000  -17.86050000
 H      5.74080000   42.30330000  -16.52830000
 C      7.25890000   39.99960000  -16.77820000
 H      7.92080000   40.18840000  -17.47570000
 H      7.46820000   40.52540000  -15.97810000
 H      7.28100000   39.04510000  -16.55680000
$end

$rem
   METHOD           = PBE50
   BASIS            = USER1
 thresh=12
   ECP        gen
   ECP_FIT    true
   SCF_GUESS   CORE
   SYMMETRY         = off
   SYM_IGNORE       = true
   UNRESTRICTED     = true
   CDFTCI           = true
   CDFTCI_PRINT     = 2
   SCF_ALGORITHM        RCA_DIIS
   CDFT_THRESH      = 7
   mem_total  =  120000
   mem_static =  1000
   threads 24
$end

$ecp
I     0
I-ECP     3     46
f potential
  5
0      1.0715702             -0.0747621
1     44.1936028            -30.0811224
2     12.9367609            -75.3722721
2      3.1956412            -22.0563758
2      0.8589806             -1.6979585
s-f potential
  5
0    127.9202670              2.9380036
1     78.6211465             41.2471267
2     36.5146237            287.8680095
2      9.9065681            114.3758506
2      1.9420086             37.6547714
p-f potential
  5
0     13.0035304              2.2222630
1     76.0331404             39.4090831
2     24.1961684            177.4075002
2      6.4053433             77.9889462
2      1.5851786             25.7547641
d-f potential
  5
0     40.4278108              7.0524360
1     28.9084375             33.3041635
2     15.6268936            186.9453875
2      4.1442856             71.9688361
2      0.9377235              9.3630657
****
$end

$cdft
   0
   1.0   1   96
   0
   1.0   1   96 S
--------------
   1
   1.0   1   96
   1
   1.0   1   96 S
$end

sorry. I still got a error message ¨ SCF failed to converge¨

I can’t test this without your custom basis set.

Have you checked whether it’s a CDFT problem? That is, does it converge as normal DFT when you turn off the constraints?

Thanks for your reply. The custom basis set provided below. I will test the normal DFT.

I     0
S   2   1.00
      0.7242000             -2.9731048
      0.4653000              3.4827643
S   1   1.00
      0.1336000              1.0000000
P   2   1.00
      1.2900000             -0.2092377
      0.3180000              1.1035347
P   1   1.00
      0.1053000              1.0000000
****
H     0
S   3   1.00
      0.1873113696D+02       0.3349460434D-01
      0.2825394365D+01       0.2347269535D+00
      0.6401216923D+00       0.8137573261D+00
S   1   1.00
      0.1612777588D+00       1.0000000
****
C     0
S   6   1.00
      0.3047524880D+04       0.1834737132D-02
      0.4573695180D+03       0.1403732281D-01
      0.1039486850D+03       0.6884262226D-01
      0.2921015530D+02       0.2321844432D+00
      0.9286662960D+01       0.4679413484D+00
      0.3163926960D+01       0.3623119853D+00
SP   3   1.00
      0.7868272350D+01      -0.1193324198D+00       0.6899906659D-01
      0.1881288540D+01      -0.1608541517D+00       0.3164239610D+00
      0.5442492580D+00       0.1143456438D+01       0.7443082909D+00
SP   1   1.00
      0.1687144782D+00       0.1000000000D+01       0.1000000000D+01
D   1   1.00
      0.8000000000D+00       1.0000000
****
N     0
S   6   1.00
      0.4173511460D+04       0.1834772160D-02
      0.6274579110D+03       0.1399462700D-01
      0.1429020930D+03       0.6858655181D-01
      0.4023432930D+02       0.2322408730D+00
      0.1282021290D+02       0.4690699481D+00
      0.4390437010D+01       0.3604551991D+00
SP   3   1.00
      0.1162636186D+02      -0.1149611817D+00       0.6757974388D-01
      0.2716279807D+01      -0.1691174786D+00       0.3239072959D+00
      0.7722183966D+00       0.1145851947D+01       0.7408951398D+00
SP   1   1.00
      0.2120314975D+00       0.1000000000D+01       0.1000000000D+01
D   1   1.00
      0.8000000000D+00       1.0000000
****
Si     0
S   6   1.00
      0.1611590000D+05       0.1959480216D-02
      0.2425580000D+04       0.1492880164D-01
      0.5538670000D+03       0.7284780801D-01
      0.1563400000D+03       0.2461300271D+00
      0.5006830000D+02       0.4859140535D+00
      0.1701780000D+02       0.3250020358D+00
SP   6   1.00
      0.2927180000D+03      -0.2780941415D-02       0.4438264521D-02
      0.6987310000D+02      -0.3571461817D-01       0.3266793328D-01
      0.2233630000D+02      -0.1149850585D+00       0.1347211372D+00
      0.8150390000D+01       0.9356344760D-01       0.3286783348D+00
      0.3134580000D+01       0.6030173068D+00       0.4496404580D+00
      0.1225430000D+01       0.4189592131D+00       0.2613722662D+00
SP   3   1.00
      0.1727380000D+01      -0.2446310042D+00      -0.1779510605D-01
      0.5729220000D+00       0.4315737717D-02       0.2535390863D+00
      0.2221920000D+00       0.1098184508D+01       0.8006692724D+00
SP   1   1.00
      0.7783690000D-01       0.1000000000D+01       0.1000000000D+01
D   1   1.00
      0.4500000000D+00       1.0000000
****

After removing the CDFT keyword, the task runs successfully with the following modified input file (qchem version: Q-Chem 6.0.2):

!QSYS wt=336:00:00
!qsys scratch 100g

$molecule
0 1
 I      3.97660000    5.22820000    6.91860000
 I      4.16030000    8.74720000    7.89810000
 Si     4.71110000    3.26720000   -1.29420000
 C      4.54380000    6.24180000   -0.75200000
 C      4.55910000    5.08410000   -1.02080000
 C      4.53980000    7.61200000   -0.38010000
 C      4.43890000    7.99440000    0.98070000
 N      4.32660000    7.02200000    1.90820000
 C      4.26600000    7.40550000    3.17220000
 C      4.15610000    6.39800000    4.19820000
 H      4.11880000    5.47980000    3.95730000
 C      4.10570000    6.75540000    5.50580000
 C      4.14180000    8.15220000    5.88920000
 C      4.21380000    9.12590000    4.94320000
 H      4.21450000   10.03850000    5.20700000
 C      4.28830000    8.79150000    3.55960000
 N      4.38390000    9.77120000    2.65780000
 C      4.47640000    9.39240000    1.36920000
 C      6.39270000    2.78000000   -0.55730000
 H      6.52250000    1.80170000   -0.71860000
 C      7.54400000    3.51940000   -1.24040000
 H      8.39040000    3.27170000   -0.81310000
 H      7.40640000    4.48620000   -1.15690000
 H      7.57270000    3.27440000   -2.18870000
 C      6.41010000    3.00640000    0.95060000
 H      7.30350000    2.80670000    1.30060000
 H      5.75320000    2.41740000    1.37690000
 H      6.18500000    3.94050000    1.14320000
 C      4.68780000    2.94420000   -3.15550000
 H      5.51570000    3.37290000   -3.51710000
 C      4.79870000    1.46950000   -3.50340000
 H      4.94290000    1.37140000   -4.46790000
 H      3.97120000    1.01070000   -3.24850000
 H      5.55360000    1.07530000   -3.01850000
 C      3.51390000    3.63210000   -3.86790000
 H      3.62050000    3.53900000   -4.83770000
 H      3.49970000    4.58290000   -3.63070000
 H      2.67250000    3.21360000   -3.59010000
 C      3.30510000    2.48730000   -0.30570000
 H      3.37530000    2.85880000    0.62010000
 C      3.44940000    0.96660000   -0.16920000
 H      2.70700000    0.61470000    0.36510000
 H      4.29840000    0.75730000    0.27330000
 H      3.43480000    0.55590000   -1.05890000
 C      1.91670000    2.85960000   -0.80900000
 H      1.25480000    2.67080000   -0.11150000
 H      1.70740000    2.33380000   -1.60910000
 H      1.89460000    3.81410000   -1.03040000
 I      5.17450000   12.79620000   -6.91860000
 I      4.99080000    9.27710000   -7.89790000
 Si     4.43990000   14.75720000    1.29420000
 C      4.60720000   11.78260000    0.75200000
 C      4.59180000   12.94020000    1.02080000
 C      4.61120000   10.41240000    0.38010000
 C      4.71220000   10.03000000   -0.98070000
 N      4.82440000   11.00240000   -1.90820000
 C      4.88500000   10.61890000   -3.17220000
 C      4.99480000   11.62640000   -4.19820000
 H      5.03220000   12.54440000   -3.95730000
 C      5.04530000   11.26880000   -5.50580000
 C      5.00910000    9.87210000   -5.88910000
 C      4.93710000    8.89850000   -4.94320000
 H      4.93650000    7.98570000   -5.20700000
 C      4.86270000    9.23320000   -3.55980000
 N      4.76710000    8.25320000   -2.65780000
 C      4.67450000    8.63190000   -1.36900000
 C      2.75830000   15.24440000    0.55730000
 H      2.62850000   16.22270000    0.71860000
 C      1.60700000   14.50480000    1.24040000
 H      0.76060000   14.75260000    0.81310000
 H      1.74460000   13.53820000    1.15690000
 H      1.57830000   14.75000000    2.18870000
 C      2.74090000   15.01800000   -0.95060000
 H      1.84750000   15.21760000   -1.30040000
 H      3.39780000   15.60700000   -1.37690000
 H      2.96600000   14.08390000   -1.14320000
 C      4.46320000   15.08020000    3.15550000
 H      3.63530000   14.65160000    3.51710000
 C      4.35230000   16.55490000    3.50340000
 H      4.20810000   16.65290000    4.46790000
 H      5.17980000   17.01390000    3.24850000
 H      3.59750000   16.94900000    3.01850000
 C      5.63710000   14.39210000    3.86790000
 H      5.53050000   14.48540000    4.83770000
 H      5.65130000   13.44150000    3.63070000
 H      6.47860000   14.81080000    3.59010000
 C      5.84590000   15.53710000    0.30570000
 H      5.77570000   15.16560000   -0.62010000
 C      5.70160000   17.05780000    0.16920000
 H      6.44390000   17.40960000   -0.36510000
 H      4.85270000   17.26700000   -0.27330000
 H      5.71620000   17.46850000    1.05890000
 C      7.23430000   15.16480000    0.80900000
 H      7.89620000   15.35360000    0.11150000
 H      7.44360000   15.69060000    1.60910000
 H      7.25640000   14.21030000    1.03040000
 I      4.00120000   30.06290000  -10.66860000
 I      4.18490000   33.58200000   -9.68910000
 Si     4.73570000   28.10200000  -18.88150000
 C      4.56840000   31.07660000  -18.33920000
 C      4.58380000   29.91890000  -18.60800000
 C      4.56440000   32.44670000  -17.96730000
 C      4.46350000   32.82910000  -16.60650000
 N      4.35120000   31.85680000  -15.67900000
 C      4.29060000   32.24020000  -14.41500000
 C      4.18070000   31.23280000  -13.38900000
 H      4.14340000   30.31460000  -13.62990000
 C      4.13030000   31.59020000  -12.08140000
 C      4.16650000   32.98690000  -11.69800000
 C      4.23850000   33.96070000  -12.64400000
 H      4.23910000   34.87330000  -12.38020000
 C      4.31290000   33.62620000  -14.02760000
 N      4.40850000   34.60600000  -14.92940000
 C      4.50110000   34.22720000  -16.21800000
 C      6.41730000   27.61470000  -18.14450000
 H      6.54710000   26.63650000  -18.30580000
 C      7.56860000   28.35420000  -18.82760000
 H      8.41500000   28.10650000  -18.40030000
 H      7.43100000   29.32090000  -18.74410000
 H      7.59730000   28.10910000  -19.77590000
 C      6.43470000   27.84120000  -16.63660000
 H      7.32810000   27.64150000  -16.28660000
 H      5.77780000   27.25220000  -16.21030000
 H      6.20960000   28.77530000  -16.44400000
 C      4.71240000   27.77890000  -20.74270000
 H      5.54030000   28.20770000  -21.10430000
 C      4.82330000   26.30420000  -21.09060000
 H      4.96750000   26.20620000  -22.05510000
 H      3.99580000   25.84540000  -20.83570000
 H      5.57820000   25.91010000  -20.60570000
 C      3.53850000   28.46690000  -21.45520000
 H      3.64510000   28.37370000  -22.42490000
 H      3.52430000   29.41770000  -21.21790000
 H      2.69720000   28.04830000  -21.17730000
 C      3.32970000   27.32210000  -17.89290000
 H      3.39990000   27.69360000  -16.96710000
 C      3.47400000   25.80130000  -17.75640000
 H      2.73160000   25.44950000  -17.22210000
 H      4.32300000   25.59210000  -17.31390000
 H      3.45940000   25.39070000  -18.64610000
 C      1.94130000   27.69440000  -18.39620000
 H      1.27940000   27.50550000  -17.69870000
 H      1.73200000   27.16850000  -19.19630000
 H      1.91920000   28.64890000  -18.61760000
 I      5.19910000   37.63100000  -24.50580000
 I      5.01540000   34.11190000  -25.48510000
 Si     4.46450000   39.59190000  -16.29300000
 C      4.63190000   36.61740000  -16.83520000
 C      4.61650000   37.77500000  -16.56640000
 C      4.63580000   35.24720000  -17.20710000
 C      4.73680000   34.86480000  -18.56790000
 N      4.84900000   35.83710000  -19.49540000
 C      4.90970000   35.45370000  -20.75940000
 C      5.01940000   36.46110000  -21.78550000
 H      5.05680000   37.37920000  -21.54450000
 C      5.06990000   36.10360000  -23.09310000
 C      5.03370000   34.70690000  -23.47630000
 C      4.96180000   33.73320000  -22.53040000
 H      4.96110000   32.82040000  -22.79430000
 C      4.88730000   34.06790000  -21.14700000
 N      4.79170000   33.08790000  -20.24500000
 C      4.69910000   33.46670000  -18.95620000
 C      2.78290000   40.07920000  -17.02990000
 H      2.65310000   41.05750000  -16.86860000
 C      1.63160000   39.33950000  -16.34680000
 H      0.78520000   39.58740000  -16.77410000
 H      1.76920000   38.37300000  -16.43030000
 H      1.60300000   39.58480000  -15.39850000
 C      2.76550000   39.85270000  -18.53780000
 H      1.87210000   40.05230000  -18.88760000
 H      3.42240000   40.44170000  -18.96410000
 H      2.99060000   38.91870000  -18.73040000
 C      4.48780000   39.91500000  -14.43170000
 H      3.65990000   39.48640000  -14.07010000
 C      4.37690000   41.38970000  -14.08380000
 H      4.23280000   41.48770000  -13.11940000
 H      5.20440000   41.84870000  -14.33870000
 H      3.62210000   41.78380000  -14.56870000
 C      5.66170000   39.22690000  -13.71930000
 H      5.55510000   39.32020000  -12.74950000
 H      5.67590000   38.27620000  -13.95650000
 H      6.50320000   39.64560000  -13.99710000
 C      5.87050000   40.37180000  -17.28150000
 H      5.80030000   40.00030000  -18.20730000
 C      5.72620000   41.89260000  -17.41800000
 H      6.46850000   42.24440000  -17.95230000
 H      4.87730000   42.10180000  -17.86050000
 H      5.74080000   42.30330000  -16.52830000
 C      7.25890000   39.99960000  -16.77820000
 H      7.92080000   40.18840000  -17.47570000
 H      7.46820000   40.52540000  -15.97810000
 H      7.28100000   39.04510000  -16.55680000
$end

$rem
   METHOD           = PBE50
   BASIS            = USER1
 thresh=12
   ECP        gen
   ECP_FIT    true
   SCF_GUESS   CORE
   SYMMETRY         = off
   SYM_IGNORE       = true
   UNRESTRICTED     = true
   SCF_ALGORITHM        RCA_DIIS
   mem_total  =  120000
   mem_static =  1000
   threads 24
$end

$ecp
I     0
I-ECP     3     46
f potential
  5
0      1.0715702             -0.0747621
1     44.1936028            -30.0811224
2     12.9367609            -75.3722721
2      3.1956412            -22.0563758
2      0.8589806             -1.6979585
s-f potential
  5
0    127.9202670              2.9380036
1     78.6211465             41.2471267
2     36.5146237            287.8680095
2      9.9065681            114.3758506
2      1.9420086             37.6547714
p-f potential
  5
0     13.0035304              2.2222630
1     76.0331404             39.4090831
2     24.1961684            177.4075002
2      6.4053433             77.9889462
2      1.5851786             25.7547641
d-f potential
  5
0     40.4278108              7.0524360
1     28.9084375             33.3041635
2     15.6268936            186.9453875
2      4.1442856             71.9688361
2      0.9377235              9.3630657
****
$end

So something about the constraint is preventing convergence. I have seen this occasionally; note there is no guarantee that a constrained solution can be found, for any given (arbitrary) constraint.