as: blue- N; grey- metal; white- hydrogen; black- carbon.
The structure of the triaminoguanidinium (TAG) cation is
shown above its unit cell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
Fig. 3.3
Electronic structure of the azido anion by HSE06 in a periodic
box, N 3
− . a Projected Crystal Overlap Hamilton population
(pCOHP) for a TZVP (blue) and STO-6G (black) basis set. A
high-level basis set leads to spurious results, [71] hence use of
a minimal basis set. b The ‘density of states’ for the azido
anion, with visualisation of the associated molecular orbitals.
Figure from Ref. [1], https://doi.org/10.1021/acs.jpcc.
8b05285. Copyright 2018 American Chemical Society. . . . . . . . 74
Fig. 3.4
Electronic band structures (HSE06) for the energetic azides.
Band dispersions are plotted along high symmetry lines. The
partial density of states are plotted for each, decomposed as
(blue) N
À
3 channel and (green) cation channel . . . . . . . . . . . . . . 75
Fig. 3.5
Potential energy surfaces (PES) associated with the N
À
3 anion.
PES are shown for a elongation of a single N…N covalent
bond, and the three symmetry independent normal modes:
b d h NNN , c dR S , and d dR A ; r 1 = (r eqm + a/10),
r 2 = (r eqm − a/10), where r eqm is the equilibrium bond distance.
In each case the potential energy surface for S 0 (black), S 1
(red), S 2 (blue), T 1 (pink) and T 2 (green) are given. All
energies are normalized to the S 0 equilibrium energies.
Figure from Ref. [1], https://doi.org/10.1021/acs.jpcc.
8b05285. Copyright 2018 American Chemical Society. . . . . . . . 78
Fig. 3.6
The PES for the symmetric stretch at a h NNN = 150° and b
h NNN = 130°. In each case the potential energy surface for S 0
(black), S 1 (red), S 2 (blue), T 1 (pink) and T 2 (green) are given.
Figure from Ref. [1], https://doi.org/10.1021/acs.jpcc.
8b05285. Copyright 2018 American Chemical Society. . . . . . . . 80
Fig. 3.7
Elongation of R 2 for N 3
− with a h NNN ¼ 150
, b h NNN ¼ 120
,
c h NNN ¼ 110
and d h NNN ¼ 100
. In each case the potential
energy surface for S 0 (black), S 1 (red), S 2 (blue), T 1 (pink) and
T 2 (green) are given . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
Fig. 3.8
Inelastic neutron spectra of a-NaN 3 at 10 K obtained on the
TOSCA spectrometer. a The experimental spectrum (top) is
shown alongside the simulated INS spectra (bottom) using
PBE-D2 (blue) and PBE-TS (green) methods. The INS
spectrum is truncated at 1500 cm
−1 , as no bands are observed
above this frequency. No LO-TO correction is included in the
simulated spectra and only first order quantum events are
included. b Modelling of the INS spectrum based on the
xx
List of Figures
The structure of the triaminoguanidinium (TAG) cation is
shown above its unit cell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
Fig. 3.3
Electronic structure of the azido anion by HSE06 in a periodic
box, N 3
− . a Projected Crystal Overlap Hamilton population
(pCOHP) for a TZVP (blue) and STO-6G (black) basis set. A
high-level basis set leads to spurious results, [71] hence use of
a minimal basis set. b The ‘density of states’ for the azido
anion, with visualisation of the associated molecular orbitals.
Figure from Ref. [1], https://doi.org/10.1021/acs.jpcc.
8b05285. Copyright 2018 American Chemical Society. . . . . . . . 74
Fig. 3.4
Electronic band structures (HSE06) for the energetic azides.
Band dispersions are plotted along high symmetry lines. The
partial density of states are plotted for each, decomposed as
(blue) N
À
3 channel and (green) cation channel . . . . . . . . . . . . . . 75
Fig. 3.5
Potential energy surfaces (PES) associated with the N
À
3 anion.
PES are shown for a elongation of a single N…N covalent
bond, and the three symmetry independent normal modes:
b d h NNN , c dR S , and d dR A ; r 1 = (r eqm + a/10),
r 2 = (r eqm − a/10), where r eqm is the equilibrium bond distance.
In each case the potential energy surface for S 0 (black), S 1
(red), S 2 (blue), T 1 (pink) and T 2 (green) are given. All
energies are normalized to the S 0 equilibrium energies.
Figure from Ref. [1], https://doi.org/10.1021/acs.jpcc.
8b05285. Copyright 2018 American Chemical Society. . . . . . . . 78
Fig. 3.6
The PES for the symmetric stretch at a h NNN = 150° and b
h NNN = 130°. In each case the potential energy surface for S 0
(black), S 1 (red), S 2 (blue), T 1 (pink) and T 2 (green) are given.
Figure from Ref. [1], https://doi.org/10.1021/acs.jpcc.
8b05285. Copyright 2018 American Chemical Society. . . . . . . . 80
Fig. 3.7
Elongation of R 2 for N 3
− with a h NNN ¼ 150
, b h NNN ¼ 120
,
c h NNN ¼ 110
and d h NNN ¼ 100
. In each case the potential
energy surface for S 0 (black), S 1 (red), S 2 (blue), T 1 (pink) and
T 2 (green) are given . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
Fig. 3.8
Inelastic neutron spectra of a-NaN 3 at 10 K obtained on the
TOSCA spectrometer. a The experimental spectrum (top) is
shown alongside the simulated INS spectra (bottom) using
PBE-D2 (blue) and PBE-TS (green) methods. The INS
spectrum is truncated at 1500 cm
−1 , as no bands are observed
above this frequency. No LO-TO correction is included in the
simulated spectra and only first order quantum events are
included. b Modelling of the INS spectrum based on the
xx
List of Figures