Sign of the Quadrupole Interaction ofLi6in LiCl

The sign of the quadrupole interaction energy of ${\mathrm{Li}}^6$ in LiCl has keen found to be positive. Previous determinations have shown that the quadrupole interaction energy of ${\mathrm{Li}}^7$ in the same molecule is also positive. It may, therefore, be concluded that both of the stable isotopes of lithium have a quadrupole moment of the same sign, though the sign itself is not known.