This hypothesis has in fact been confirmed, inter alia by spectroscopical investigations into light sources placed in very strong magnetic fields.    From Wordnik.com.  [Nobel Prize in Physics 1943 and 1944 - Presentation Speech] Reference

It was only natural that precedence was given to the investigations first named, as a fruitful spectroscopical investigation of X-rays presupposed a certain knowledge of the lattice used.    From Wordnik.com.  [Nobel Prize in Physics 1924 - Presentation Speech] Reference

It had already become clear that the X-radiation must arise in the inner parts of the atoms, and that consequently exact X-ray spectroscopical investigations form the only means for an experimental research of those parts.    From Wordnik.com.  [Nobel Prize in Physics 1924 - Presentation Speech] Reference

NMR-spectroscopical research on proteins and peptides, Bavarian NMR-Center, http://www. e22.physik.tu-muenchen.de/bausch.    From Wordnik.com.  [EurekAlert! - Breaking News] Reference