Related papers: Precision spectroscopy of the 3s-3p fine structure…
Absolute transition frequencies of the $2s\; ^2{\rm S}_{1/2} \rightarrow 2p\;^2\mathrm{P}_{1/2,3/2}$ transitions in Be$^+$ were measured for the isotopes $^{7,9-12}$Be. The fine structure splitting of the $2p$ state and its isotope…
The unusually large hyperfine structure splittings in the 23P state of the 3He isotope is measured using electro-optic techniques with high precision laser spectroscopy. Originally designed to probe the fine structure of the 4He atom, this…
We describe a high-resolution spectroscopy method, in which the detection of single excitation events is enhanced by a complete loss of coherence of a superposition of two ground states. Thereby, transitions of a single isolated atom nearly…
We report a microwave spectroscopy measurement of the muonium $2S_{1/2}-2P_{3/2}$ fine structure transition, yielding a transition frequency of $9871.0 \pm 7.0~\mathrm{MHz}$, in agreement with state-of-the-art QED predictions within one…
Absolute transition frequencies of the $2s\,^2{\rm{S}}_{1/2}$ $\rightarrow$ $2p\,^2{\rm{P}}_{1/2,3/2}$ transitions in Be$^+$ were measured with a frequency comb in stable and short-lived isotopes at ISOLDE (CERN) using collinear laser…
We have measured transition frequencies, isotope shifts and hyperfine structure splittings in the $3 d^{2}\left({ }^{3\!}F\right) 4 s\,{ }^{4} F_J\rightarrow 3 d^{2}\left({ }^{3\!} F\right) 4 p \,^{4} G_{J+1}$ transitions in Ti$^+$ ions for…
We demonstrate an efficient high-precision optical spectroscopy technique for single trapped ions with non-closed transitions. In a double-shelving technique, the absorption of a single photon is first amplified to several phonons of a…
We report measurements of the isotope shifts of the (3s3p)$^3$P$_{0,1,2}$ - (3s4s)$^3$S$_1$ Mg I transitions for the stable isotopes $^{24}$Mg (I=0), $^{25}$Mg (I=5/2) and $^{26}$Mg (I=0). Furthermore the $^{25}$Mg $^3$S$_1$ hyperfine…
Doppler-free saturated absorption spectroscopy is performed on an enriched radioactive Ar-39 sample. The spectrum of the 3s^2 3p^5 4s [3/2]_2 - 3s^2 3p^5 4p [5/2]_3 cycling transition at 811.8 nm is recorded, and its isotope shift between…
We demonstrate a method for precision spectroscopy on trapped ions in the limit of unresolved motional sidebands. By sympathetic cooling of a chain of crystallized ions we suppress adverse temperature variations induced by the spectroscopy…
We report measurements and theoretical calculations of the fine-structure splittings in all three $1s2s\,^3\!S_1\rightarrow\,1s2p\,^3\!P_{0,1,2}$ transitions in the heliumlike systems of the isotopes $^{12,13,14}$C. The metastable triplet…
Quasar spectra reveal a rich array of important astrophysical information about galaxies which intersect the quasar line of sight. They also enable tests of the variability of fundamental constants over cosmological time and…
We calculate the dependence of atomic transition frequencies on the fine structure constant, $\alpha = e^2/\hbar c$, for some ions of Ti, Mn, Na, C, and O. The results of these calculations will be used in the search for variation of alpha…
Theories unifying gravity with other interactions suggest spatial and temporal variation of fundamental "constants" in the Universe. A change in the fine structure constant, alpha, could be detected via shifts in the frequencies of atomic…
Precision spectroscopy of atomic hydrogen is an important way to test bound-state quantum electrodynamics (QED), one of the building blocks of the Standard Model. In its simplest form, such a test consists of the comparison of a measured…
The hyperfine structure and isotope shifts of the 3s23p2 3P2 to 3s3p3 3Do3 transition in silicon have been measured. The transition at 221.7 nm was studied by laser induced fluorescence in an atomic Si beam. For 29Si, the hyperfine A…
We measured the isotope shift in the $^2$S$_{1/2}$-$^2$P$_{3/2}$ (D2) transition in singly-ionized calcium ions using photon recoil spectroscopy. The high accuracy of the technique enables us to resolve the difference between the isotope…
Direct frequency comb spectroscopy of trapped ions is demonstated for the first time. It is shown that the 4s^2S_(1/2)-4p^2P_(3/2) transition in calcium ions can be excited directly with a frequency comb laser that is upconverted to 393 nm.…
Theories unifying gravity with other interactions suggest spatial and temporal variation of fundamental ``constants'' in the Universe. A change in the fine structure constant, alpha, could be detected via shifts in the frequencies of atomic…
We present an accurate ab initio method of calculating transition energies and isotope shifts in the 3d-transition metals. It extends previous work that combines the configuration-interaction calculation with many-body perturbation theory…