Fig. 6: Ļ-bonding molecular orbitals (MOs) of AzPy and AzPyH+.
From: A cautionary tale of basic azo photoswitching in dichloromethane finally explained

a \(\pi\)-bonding MO of trans-AzPy. b \(\pi\)-bonding MO of trans-AzPyH+ polarized towards the pyridinium ring. MOs were calculated at the BH&HLYP-D3(BJ)/def2-QZVPP level.