強結合近似
E x , 3 z 2 − r 2 = l [ n 2 − ( l 2 + m 2 ) / 2 ] V p d σ − 3 l n 2 V p d π {\displaystyle E_{x,3z^{2}-r^{2}}=l[n^{2}-(l^{2}+m^{2})/2]V_{pd\sigma }-{\sqrt {3}}ln^{2}V_{pd\pi }}
E y , 3 z 2 − r 2 = m [ n 2 − ( l 2 + m 2 ) / 2 ] V p d σ − 3 m n 2 V p d π {\displaystyle E_{y,3z^{2}-r^{2}}=m[n^{2}-(l^{2}+m^{2})/2]V_{pd\sigma }-{\sqrt {3}}mn^{2}V_{pd\pi }}
E z , 3 z 2 − r 2 = n [ n 2 − ( l 2 + m 2 ) / 2 ] V p d σ + 3 n ( l 2 + m 2 ) V p d π {\displaystyle E_{z,3z^{2}-r^{2}}=n[n^{2}-(l^{2}+m^{2})/2]V_{pd\sigma }+{\sqrt {3}}n(l^{2}+m^{2})V_{pd\pi }}
E x y , x y = 3 l 2 m 2 V d d σ + ( l 2 + m 2 − 4 l 2 m 2 ) V d d π + ( n 2 + l 2 m 2 ) V d d δ {\displaystyle E_{xy,xy}=3l^{2}m^{2}V_{dd\sigma }+(l^{2}+m^{2}-4l^{2}m^{2})V_{dd\pi }+(n^{2}+l^{2}m^{2})V_{dd\delta }}