How do you optimize an organo-metalic compound containing cerium in in Gaussian?

I am trying to perform optimisation of the molecule attached. I need to get partial charges and frequencies. The issue is that it doesn't converge with following input:



```
%nprocshared=8
%mem=16GB
%chk=CTB.chk
#n opt b3lyp/gen pop=(ReadRadii, savechelpg) SCF=QC
CTB
0 2
Ce -6.41954 5.21611 0.61820
...
N -4.38490 3.87720 0.35349

H -5.52145 4.13584 -2.66372
Ce 0
SDD
****
H Si C N 0
6-31G
****
Ce 2.88

```

As well I get error message:
Restarting incremental Fock formation.
Gradient too large for Newton-Raphson or scaled steepest descent --
use steepest descent instead.


[![](https://i.stack.imgur.com/tGdsU.png)](https://i.stack.imgur.com/tGdsU.png)


