2-Nitrophenol Gas Assignment Region λ(nm) E (eV) ( f ) Major contribution 279.57 4.434 0.247 L®H+1 (90%) n→π* Quartz UV 274.66 4.514 0.012 L®H+1 (88%) n→π* Quartz UV 224.92 5.512 0.033 H®L-1 (92%) n→π* Quartz UV 2,6-Nitrophenol 330.87 3.747 0.057 H®L (94%) π→π* Quartz UV 319.78 3.877 0.016 H®L (93%) π→π* Quartz UV 305.49 4.058 0.007 H®L (86%) n→π* Quartz UV 291.39 4.255 0.004 H®L (86%) n→π* Quartz UV 2,4,6-Nitrophenol 418.51 2.962 0.001 H®L (86%) - Visible 374.54 3.310 0.001 H®L (86%) n→π* Quartz UV 370.89 3.342 0.00 H®L (86%) n→π* Quartz UV

H: HOMO; L: LUMO

Table 7: Electronic absorption spectra of 2,4,6-Nitrophenol (absorption wavelength λ(nm), excitation energies E (eV) and oscillator strengths (f)) using TD-DFT/ B3LYP/6-311++G(d,p) method gas phase.