Large-scale multiconfigurational Dirac-Fock calculations of the hyperfine-structure constants and determination of the nuclear quadrupole moment of Ti-49

The multiconfiguration Dirac-Fock (MCDF) model is employed to compute the h yperfine interaction constants of the 3d(2)4s D-2(3/2), 3d(2)4s D-2(5/2), 3 d(3) 2G(7/2), 3d(3) (2)G(7/2), and 3d(3) P-2(3/2) levels of titanium ion. T he wave function expansions are obtained with the active space expansion me thod, where configuration state functions of a specific parity and J value are generated by substitutions from the reference configurations to an acti ve set of orbitals. The active set is then increased in a systematic way, a llowing the convergence of the expectation values to be achieved. The calcu lated electric quadrupole hyperfine constants are used to evaluate the nucl ear electric quadrupole moment of isotope 49 of titanium, for which the val ue Q = 0.247( Il)b is found. [S1050-2947(99)04906-9].