PHOTOACOUSTIC INVESTIGATION OF THE RELAXATION OF THE 2E STATE OF RUBY M. Gallmeier, E. Strauss, R. Germer, W. Schubert, R.T. Brundage and W.M. Yen J. Phys. Colloques, 44 C6 (1983) C6-401-C6-405 DOI: 10.1051/jphyscol:1983666