Table 1.

Calculated properties of HCN (1, 2) and 1D pI chains 3–8

MaterialΔE*, kcal/molBand gap, eVN=C–C=N dihedral angle, °
1. HCN (g)17.8
2. HCN (s)9.6
3. pI threefold helix1.74.5110
4. pI fourfold helix2.44.368
5. pI fivefold helix4.53.839
6. pI sixfold helix2.13.526
7. pI wave0.02.2∼3
8. pI planar0.81.50
  • * Energies per unit of HCN are from periodic HSE06 calculations, and are shown relative to the lowest energy structure 7.

  • Average value for all N=C–C=N dihedral angles in the unit cell.