Laser probing of ions confined in a cylindrical radiofrequency trap

High-Resol Ution Spectroscopy of Stored Ions

“…However, at high vacuum other coupling mechanisms can occur partly due to the presence of impurity i o n s or imperfections in the trap electrodes. This process can give kinetic energies of ions of as much as electron volts and shortened storage times of less than 1 s. If one uses a light buffer gas such as He to provide viscous damping [l] then storage times of many days can be achieved [19,20]. However, this increases perturbations due to collisions; therefore, for experiments on large numbers of ions in an rf trap, there appears to be a practical tradeoff between the temperature of the ions and possible perturbations due to collisions with a cooling buffer gas.…”

Pulsed fluorescence measurements of trapped molecular ions with zero background detection

“…To investigate the quantitative capability of these fluorescence techniques, the laser-induced fragmentation of trapped Alexa I on traps provide a controlled environment in which fluorescence measurements can be performed on an ensemble of ions over timescales sufficient to consider small ion numbers and slow reaction rates. Laserinduced fluorescence measurements of trapped ions have been used in spectroscopic studies of atomic structure [1][2][3][4], the vibrational spectra of small molecules [5][6][7][8], as well as to characterize the dynamic cooling [9] and crystallization of atomic ions [10 -12].This paper introduces techniques that eliminate the detection of laser background scattering on trap apertures and internal surfaces allowing measurements to achieve both high sensitivity and large dynamic range. In previous pulsed laser measurements of molecular fluorescence collected from trapped species (discussed in references [5][6][7][8]), the radiative lifetimes were sufficiently long to allow collection of fluorescence radiation after the laser pulse.…”

“…To investigate the quantitative capability of these fluorescence techniques, the laser-induced fragmentation of trapped Alexa I on traps provide a controlled environment in which fluorescence measurements can be performed on an ensemble of ions over timescales sufficient to consider small ion numbers and slow reaction rates. Laserinduced fluorescence measurements of trapped ions have been used in spectroscopic studies of atomic structure [1][2][3][4], the vibrational spectra of small molecules [5][6][7][8], as well as to characterize the dynamic cooling [9] and crystallization of atomic ions [10 -12].…”

“…Rhodamine 640 and Alexa Fluor 350 ions, commonly used as fluorescence resonance energy transfer (FRET) fluorophores, were generated in the gas phase by using electrospray ionization and injected into a radiofrequency Paul trap where they were stored and exposed to Nd:YAG laser pulses at 532 and 355 nm for times up to 10 m. Fluorescence emitted by these ions was investigated for several trap q z values and ion cloud temperatures. Analysis of photon statistics indicated an average of ϳ10 photons were incident on the PMT detector per 15 ns pulse for ϳ10 3 I on traps provide a controlled environment in which fluorescence measurements can be performed on an ensemble of ions over timescales sufficient to consider small ion numbers and slow reaction rates. Laserinduced fluorescence measurements of trapped ions have been used in spectroscopic studies of atomic structure [1][2][3][4], the vibrational spectra of small molecules [5][6][7][8], as well as to characterize the dynamic cooling [9] and crystallization of atomic ions [10 -12].…”

Lifetime measurement of the 5d2 D 5/2 state in Ba+

“…The lifetime of the metastable 5d 2 D 5/2 state in Ba + has been measured earlier in different experiments [10][11][12][13][14][15][16]. Calculations are presently performed by different independent theory groups [5,6,[17][18][19][20][21].…”