Alexander is interested in the analysis of spectra of neutral and ionized atoms and is active in the critical compilation of atomic spectral data for NIST's atomic spectroscopy databases. He is currently involved in evaluation of energy levels, wavelengths, and transition probabilities in several spectra of atoms and atomic ions and critical evaluation of experimental and theoretical ionization energies of all stages of ionization of all chemical elements. Utilizing his knowledge of computer programming, he assists in support of the on-line databases on atomic spectra.
2015: Judson C. French Award from the National Institute of Standards and Technology, USA, “for establishing the world’s premier resource for atomic reference data, relied upon for everything from nuclear forensics to Hubble data analysis.”