Unable to construct Hamiltonian for a moleucle

Hi All,

I tried to create Hamiltonian for the molecule reported in the work (https://www.nature.com/articles/s41524-021-00540-6). The work was carried out in IBM Qiskit, I wanted to create a ground state Hamiltonian of the molecule with Active Space invoked. It gave me a following error.

“Unable to allocate 255. GiB for an array with shape (430, 430, 430, 430) and data type float64” .

I am running the calc. on 370GB RAM and 48 core system. I also noticed that throughout the job, not all the cores were occupied. I am not sure if the process is parallelized or not. Kindly help me in this regard.