Professor Christopher Foot

Abstract:

Improved measurements of isotope shifts in the 4s21S0-4s5s 1S0 transition of calcium are reported for the stable isotopes. A comparison with isotope shift measurements in other transitions by means of a King plot shows satisfactory agreement. Values of the changes in mean-square nuclear charge radius delta (r2) from a combined analysis of muonic isotope shifts and electron scattering data are used to separate the mass and field shifts in the optical lines. This procedure leads to values of delta (r2) for the calcium isotopes from 40Ca to 48Ca using all available high-precision data. The results for delta (r2)A,40 are 3.2(2.5), 215.3 (4.9), 125.4 (3.2), 283.2 (6.4), 118.8 (5.9), 124.2 (5.0), 5 (13) and -4.4(6.0)*10-3 fm2 for A=41 to 48 respectively. Values of the electronic factors relating the observed shifts of delta (r2) are deduced, and discussed in terms of configuration mixing in calcium.

Abstract:

Intra-cavity second harmonic generation in a ring dye laser using lithium formate monohydrate has been observed to produce tunable cw UV radiation around 243 nm with single frequency powers of up to 1.4 mW. This wavelength region is of particular interest in the context of Doppler-free spectroscopy of atomic hydrogen. The radiation was used to excite an atomic beam of strontium to study the transition 5s2 1S0-4d5p 1P1 of Sr I. The isotope shifts were determined as follows: 88Sr-87Sr 123.7(8) MHz; 88Sr 285.0(8) MHz; 88Sr-84Sr 600.1(9) MHz. The values are compared with results for other lines and muonic isotope shifts to obtain the specific mass shift and field shift in this transition and to study the configuration mixing effects. The hyperfine structure of 87Sr was not resolved, the intervals being very much less than the measured linewidth of 25 MHz. © 1984.