Dipole moment of PH+ and the atomic masses of 28Si, 31P by comparing cyclotron frequencies of two ions simultaneously trapped in a penning trap.
By trapping pairs of ions in a Penning trap, alternating each ion between large and small cyclotron orbits, we have measured the cyclotron frequency ratios 12C2H4+/28Si+, 13C2H2+/28Si+, 28SiH3+/31P+, and 16O2+/31PH+, all to <30 ppt precision. The 16O2+/31PH+ data exhibit a bimodal distribution due to the polarizability of the Lambda-doubling components of the PH+ ground state, from which we obtain the electric dipole moment of 31PH+, 0.331(8) ea0. Combined with other atomic mass measurements we also obtain improved values for m(28Si), 27.976 926 535 0(6) u, and m(31P), 30.973 761 998 9(9) u.
Redshaw
Matthew
M
Department of Physics, Florida State University, Tallahassee, FL 32306-4350, USA.
McDaniel
Joseph
J
Myers
Edmund G
EG