[reaction: see text] Carbon nanotube salts prepared by treating single-wall carbon nanotubes (SWNTs) with lithium in liquid ammonia react readily with aryl iodides to give SWNTs functionalized by aryl groups.
Accurate measurements are presented of the rate of trap-loss-producing collisions between ultracold magneto-optically trapped Li atoms for a range of trap laser intensities and frequencies. Intensities from near the atomic saturation intensity to well above it are investigated. At low intensities, fine-structure-changing collisions cause trap loss with a rate constant of -10 ' cm /s. At sufficiently high intensity, the trap can be deep enough to effectively freeze out the dominant fine-structure-changing collisions as a loss mechanism, [11].This ability to separate the contributions of RE and FS greatly simplifies the interpretation of the experiment. In this paper, we present measurements of the RE and FS rates in I i for a range of trap laser intensities and detunings. The measured rates are compared with calculations that account for the variation of ET with laser intensity and detuning.The experimental apparatus and procedure are similar to other measurements of collisional loss in a MOT [2,4]. The MOT consists of six near-resonant laser beams along the three orthogonal axes that provide for dissipation of the atomic kinetic energy, and, when combined with an inhomogeneous magnetic field, also produce a restoring force [1].The six beams are produced by a dye laser that is frequency locked relative to a saturated absorption feature of Li in an absorption cell to provide long-term frequency stability and a relative frequency reference. The waist (1/e intensity radius) of the laser beams is 0.64 cm. A pair of anti-Helmholtz configured coils generates an axial magnetic-field gradient of 3 mT/cm and a radial gradient of 1.5 mT/cm. To ensure a near-spherically-symmetric cloud of trapped atoms, the intensities of the four radial laser beams are equal, while the intensity of an axial beam is -60% of the intensity of a radial beam. Transitions from both I' = 1 and 2 ground-state hyperfine levels to the excited states are driven with equal intensity using the upper and lower first-order sidebands produced by a standing-wave electro-optic modulator, modulated at 406.4 MHz. The lower first-order sideband is de-
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