I am trying to simulate the Calcium Oxide (CaO) molecule and apparently the information about Calcium (Ca) is not recorded.

```
import pennylane as qml
from pennylane import numpy as np
from pennylane import qchem
simbolos=["Ca","O"]
coordenadas=np.array([[0.0, 0.0, 0.0], [2.75, 0.0, 0.0]])
H,qubits = qchem.molecular_hamiltonian(simbolos,coordenadas,charge=0)
print(qubits)
hf=qchem.hf_state(electrons=28, orbitals=qubits)
print(hf)
```

I have this error:

```
ValueError Traceback (most recent call last)
Cell In[26], line 3
1 simbolos=["O","Ca"]
2 coordenadas=np.array([[0.2, 0.3, 0.33], [2.75, 0.11, 0.9]])
----> 3 H,qubits = qchem.molecular_hamiltonian(simbolos,coordenadas,charge=1)
4 print(qubits)
6 #hf=qchem.hf_state(electrons=28, orbitals=qubits)
7 #print(hf)
File ~/Moleculas/moleculas/lib/python3.10/site-packages/pennylane/qchem/openfermion_obs.py:928, in molecular_hamiltonian(symbols, coordinates, name, charge, mult, basis, method, active_electrons, active_orbitals, mapping, outpath, wires, alpha, coeff, args, load_data, convert_tol)
926 if args is None and isinstance(geometry_dhf, qml.numpy.tensor):
927 geometry_dhf.requires_grad = False
--> 928 mol = qml.qchem.Molecule(
929 symbols,
930 geometry_dhf,
931 charge=charge,
932 mult=mult,
933 basis_name=basis,
934 load_data=load_data,
935 alpha=alpha,
936 coeff=coeff,
937 )
938 core, active = qml.qchem.active_space(
939 mol.n_electrons, mol.n_orbitals, mult, active_electrons, active_orbitals
...
---> 94 raise ValueError(f"Atoms in {set(symbols) - set(atomic_numbers)} are not supported.")
96 self.symbols = symbols
97 self.coordinates = coordinates
ValueError: Atoms in {'Ca'} are not supported.
Output is truncated. View as a scrollable element or open in a text editor. Adjust cell output settings...
```