LIFETIME, COLLISIONAL-QUENCHING, AND J-MIXING MEASUREMENTS OF THE METASTABLE 3D LEVELS OF CA+

The metastable 3(2)D(3/2,5/2) doublet of Ca+ ions stored in a Paul trap was investigated in the presence of different neutral gases, in the pressure range 10(-9)-10(-6) mbar. The natural lifetimes were determined to be tau(D-3/2)=1111+/-46 ms and tau(D-5/2)=994+/-38 ms, which agree very well with previous experiments. The estimation of the quenching rates of Ca+-He [Gamma(He)=(1.05+/-0.42)x10(-12) cm(3) s(-1)], Ca+-Ne [Gamma(Ne)=(0.9+/-0.7)x10(-12) cm(3) s(-1)], and Ca+-N-2 [Gamma N-2=(1.7+/-0.2)x10(-10) cm(3) s(-1)] was carried out for collisions in the energy range 0.3-1.3 eV. In addition, rate constants for the mixing of the fine-structure states were measured in the presence of helium and nitrogen for the j=3/2-->j=5/2 case [gamma(35)(He)= (2.24+/-0.10)x10(-10) cm(3) s(-1) and gamma(35)(N-2)=(2.8+/-0.3)x10(-9) cm(3) s(-1)] and for the j=5/2-->j=3/2 case [gamma(53)(He)=(1.2+/-0.7)x10(-10) cm(3) s(-1) and gamma(53)(N-2)=(1.26+/-0.10)X10(-9) cm(3) s(-1)]. The measurements were carried out populating the metastable levels by direct laser excitation of the forbidden S-D transitions.