HUMO-LUMO gap

Fig. 1. The bending of NO2 group out of the CNOO plane (7 53°) leads closure of the HUMO-LUMO gap. This structure is also near the equilibrium geometry of the first electronically excited state of nitromethane.

Fig.3. HUMO LUMO gap change under uniform compression. The sudden drop in the gap corresponds to the reported high C-H bond stretching.

Fig.5. (a) 2x1x1 supercell with 1 molecular vacancy, corresponding to 12.5% vacancy concentration, (b) HUMO-LUMO gap (in eV) for uniform and uniaxial compression. 

Fig.2. HUMO-LUMO energy gap of the prefect nitromethane crystal under uniform and uniaxial compression of the primitive unit cell.

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