The cell neighbor list is constructed in a similar manner as the α groups. For each cell in the system, shells of increasing thickness are assigned as either short-range neighbors or longrange neighbors for a given α group. The shell of neighboring cells immediately surrounding the current cell are assigned as short-range neighbors, then the one-cell-thick shell of cells around the short-range neighbors are assigned as long-range neighbors using the first cubature. Similar to the α groups, this process is repeated while increasing the shell thickness until all other cells in the unit cell are assigned.