Spectroscopic tests of the symmetrization postulate and of the statistics for nuclei in molecules

Abstract

We discuss the implications of the spin-statistics connection and of the symmetrization postulate on the quantum states of three identical nuclei arranged in rigid symmetrical molecules. We show that in the case of three identical nuclei a whole class of rotational states are forbidden also by the symmetrization postulate, and not only by the spin-statistics connection. We then present the experiments we are performing on NH 3 , to search for the possible existence of these states forbidden by the symmetrization postulate, and on CO 2 , to improve the sensitivity for detection of exchange-antisymmetric states of spin-0 nuclei. Preliminary results of the latter experiment indicate that violations of the statistics for oxygen nuclei, if present, are smaller than 10 −11 , with an improvement of more than two orders of magnitude with respect to previous experiments.