Resonant X-ray Emission and Valence-band Lifetime Broadening in LiNO₃

X-ray absorption and resonant inelastic x-ray scattering measurements are carried out on lithium nitrate LiNO₃. The nitrogen σ orbitals exhibit a large lifetime effect. Experimentally, this is manifest as an apparent weakening of the x-ray emission signal from these states, but a closer examination shows that instead it is due to extreme broadening. This echos previous studies on ammonium nitrate, which, despite large differences in the cation and space group, showed a similar effect associated with the nitrate. Using first-principles GW self-energy and Bethe-Salpeter equation calculations we show that this effect is due in part to short quasi-hole lifetimes for the orbitals constituting the NO σ bonds.