“…where n is the number of electrons, r i is the vector connecting the nucleus with the ith electron, r i is its length, r ij is the distance between electrons i and j, m 0 is the nucleus mass (12 786.3933m e for 7 Li and 10 961.898m e for 6 Li, where m e = 1 is the electron mass), q 0 = 3 is its charge, q i = −1 are electron charges, and μ i = m 0 m i /(m 0 + m i ) are electron reduced masses. The prime indicates the matrix/vector transpose.…”