$\to \langle VPV{P}^{5}V\rangle {\left(\Delta E_1\right)}^3\Delta E_2$

(1)

$\to \langle VPV{P}^{5}V\rangle {\left(\Delta E_1\right)}^3\Delta E_2$

(1)

$\to \langle VPV{P}^{5}V\rangle \Delta E_2{\left(\Delta E_1\right)}^3$

(1)

$\to \langle VPV{P}^{5}V\rangle \Delta E_2{\left(\Delta E_1\right)}^3$

(1)

$\to -\langle VPV{P}^{6}V\rangle {\left(\Delta E_1\right)}^5$

(1)