MÖSSBAUER STUDIES OF THE ACTIVATION OF AMMONIA SYNTHESIS CATALYSTS B. S. CLAUSEN, S. MØRUP, H. TOPSØE, R. CANDIA, E. J. JENSEN, A. BARANSKI et A. PATTEK J. Phys. Colloques, 37 C6 (1976) C6-245-C6-248 DOI: 10.1051/jphyscol:1976649