THE NUCLEAR-QUADRUPOLE MOMENT OF CS-133 - ACCURATE RELATIVISTIC COUPLED-CLUSTER CALCULATIONS FOR CSF WITHIN THE POINT-CHARGE MODEL FOR NUCLEAR-QUADRUPOLE MOMENTS

The nuclear quadrupole moment (NQM) of the 133 isotope of Cs is not ac curately known. This is due to the fact that the electric field gradie nt (EFG) of Ca for the 6p(1 2)P(3/2) excited state was only estimated from the 6p(r(-3)) expectation value using Hartree-Slater calculations . CsF microwave data yield a very accurate nuclear quadrupole coupling constant (NQCC). We therefore decided to perform relativistic coupled cluster calculations for CsF in order to obtain a more accurate value for the Cs EFG. At the highest level of theory we obtain a NQM for th e first vibrational-rotational state of -3.43(10) mb which should be m ore accurate than the previously estimated value of -3.7(1.6) mb or -9 (4) mb. (C) 1998 American Institute of Physics.