Showing papers by "H. G. Berry published in 1992"

Measurement of the 6p2P3/2 state lifetime in atomic cesium.

Abstract: We present a precision experimental test of atomic many-body theory that is currently applied to the interpretation of recent parity-nonconservation experiments in atomic cesium. We report the first measurement of the $^{133}\mathrm{Cs}$ 6p $^{2}$${\mathit{P}}_{3/2}$ state lifetime using resonant diode-laser excitation of a fast atomic beam. The lifetime result of 30.55\ifmmode\pm\else\textpm\fi{}0.27 ns determines the absorption oscillator strength for the 6s $^{2}$${\mathit{S}}_{1/2}$--6p $^{2}$${\mathit{P}}_{3/2}$ transition in cesium to be 0.7133\ifmmode\pm\else\textpm\fi{}0.0064, and establishes the accuracy of recent relativistic many-body calculations of the dipole transition matrix element to 0.5%.

Electron Transfer from H2 and Ar to Stored Multiply Charged Argon Ions Produced by Synchrotron Radiation.

Abstract: The rate coefficients for electron transfer from Ar and H{sub 2} to Ar{sup {ital q}+} ions (3{le}{ital q}{le}6) have been measured using an ion-storage technique in a Penning ion trap. The ions were produced in the trap by {ital K}-shell photoionization of Ar atoms, using broadband synchrotron x-ray radiation. {ital K}-electron removal resulted in vacancy cascading, yielding a distribution of argon-ion charge states peaked near Ar{sup 4+}. The stored ion gas had an initial temperature near 480 K. The basic data determining the rate coefficients {ital k}(Ar{sup {ital q}+}) are the storage time constants of each charge state in the trap, in the presence of a measured pressure of target gas. The results of the measurements (in units of 10{sup {minus}9} cm{sup 3} s{sup {minus}1}) are {ital k}(Ar{sup 3+},H{sub 2})=4.3(0.7), {ital k}(Ar{sup 3+},Ar)=1.6(0.2), {ital k}(Ar{sup 4+},H{sub 2})=5.2(0.6), {ital k}(Ar{sup 4+},Ar)=2.5(0.3), {ital k}(Ar{sup 5+},H{sub 2})=5.9(0.7), {ital k}(Ar{sup 5+},Ar)=2.9(0.3), {ital k}(Ar{sup 6+},H{sub 2})=8.5(1.2), and {ital k}(Ar{sup 6+},Ar)=2.5(0.3).