The Quadrupole Moment of V51

The hyperfine structure (hfs) of the spectrum of V I was investigated. From the hfs of λ 4851 the quadrupole coupling constant of the ground Level 3 d 3 4 s 2 4 F 3/2 was deduced. Assuming that the screening correction for the d -electron of V I is 13, the quadrupole moment of V 51 was calculated to be (0.2 8 ±0.15)10 -24 cm 2 , in which the polarization correction due to Sternheimer is taken into account. The indicated probable error does not include the uncertainty of the screening correction of the d -electron. In addition to the hfs of λ 4851, the hfs of λλ 4881, 4875, 4832, 4594, 4330 were measured, and the interval factors of the quartet levels 3 d 3 4 s 2 4 F and of 3 d 3 4 s 4 p 4 G 11/2 were obtained.