Hi,
There is an error in the instruction in the original code:
Define the single and double excitations
singles, doubles = qchem.excitations(electrons=2, orbitals=qubits)
With this code you got this error:
Error: name ‘qchem’ is not defined.
Correction:
singles, doubles = qml.qchem.excitations(electrons=2, orbitals=qubits)
Best Regards