Laser and mass spectroscopy of fullerene and magnesium ions in a linear RF quadrupole ion trap

A linear RF quadrupole ion trap apparatus has been developed to study isolated atomic and molecular ions. This apparatus has been demonstrated to work in such a way, that it is capable of trapping heavy molecular ions such as the fullerenes. Both laser spectroscopic measurements and mass spectrometry were conducted in the ion trap. Three mass analysis techniques, namely q-scan, parametric excitation and q-secular scan, were developed and used throughout the research. Laser cooling was investigated for Mg + ions for two different configurations: one is that the UV beam is guided along the trap axis and in the second arrangement the UV beam crosses the trap axis with a 15° angle. A crude cooling model is proposed. Systematic measurements are made to investigate the effects of various factors in our model on the laser cooling effect. An external build-up cavity was developed to frequency double a tunable cw dye laser to obtain the UV beam around the wavelength of 280 nm. A theoretical treatment of the parametric resonance of the trapped ions is also given. A new detection method, based on monitoring the laser induced fluorescence signal of the trapped Mg+ ions, was developed and is used to systematically measure the parametric resonance boundaries for our specific trap geometry. Endohedral fullerenes are produced inside this trap by collision. An observation of the optical detection of the transitions of the Nd3+ ion inside a fullerene cage was also attempted.