Energies of the HOMO and LUMO, H–L gap (E_g), maximum absorption wavelength (λ_max), dipole moment, chemical potential(μ), chemical hardness (η), chemical softness (s) and global electrophilicity index (ω) of phosphorene, the drug molecule and phosphorene–drug complexes.

	E HOMO	E LUMO	E g (eV)	λ max (nm)	Dipole moment	μ (eV)	η (eV)	s (eV−1)	ω (eV)
Phosphorene	−6.01	−2.72	3.28	458	0.56	−4.37	1.64	0.30	5.82
Chlorambucil	−5.49	−0.21	5.28	269	2.37	−2.85	5.28	0.09	0.78
Phosphorene–chlorambucil	−5.43	−2.76	2.67	537	2.49	−4.1	1.33	0.37	6.32