Å⁻¹

per angstrom

Wavenumberexact by definition

The reciprocal angstrom is exactly 10¹⁰ m⁻¹. It is the standard axis of reciprocal space in crystallography and scattering: X-ray and neutron diffraction patterns are plotted against the momentum transfer q in Å⁻¹, and band structures are plotted along reciprocal lattice directions in the same unit.

Watch out: Two conventions for the scattering vector are both in circulation, differing by a factor of 2π, and papers are not always explicit about which they use. Compare a peak position against a known lattice spacing before trusting a q axis.

1 Å⁻¹ 10,000,000,000 m⁻¹