Calibration method at the N K-edge using interstitial nitrogen gas in solid-state nitrogen-containing inorganic compounds

The standard method of soft X‐ray beamline calibration at the N K‐edge uses the ν = 0 peak transition of gas‐phase N2. Interstitial N2 gas trapped or formed within widely available solid‐state ammonium‐ and amine‐containing salts can be used for this purpose, bypassing gas‐phase measurements. Evidence from non‐nitrogen‐containing compounds (KH2PO4) and from He‐purged ammonium salts suggest that production of N2 gas is through beam‐induced decomposition. Compounds with nitrate or nitrite as anions produce coincident features and are not suitable for this calibration method.