The energies of inversion can also be predicted and compared. Due to lower energy overlap between the 3p and 1s orbitals in PH 3 (versus between 2p and 1s in NH 3), the HOMO-LUMO energy gap in PH 3 will be smaller than that of NH 3. This allows for a stronger interaction between the HOMO and LUMO in second-order Jahn-Teller fashion. The distortion stabilizes the HOMO and destabilizes the LUMO, resulting in a larger barrier to inversion in PH 3.