| Zugriffsnummer | 40238 |
| Dokumenttyp | Dissertation |
| Peer Review | unbekannt |
| Sprache | Englisch |
| Titel | One and two-color photoassociation spectroscopy of ultracold 40Ca |
| Autor(in); Institution |
Pachomow, Evgenij; 4.3, Quantenoptik und Längeneinheit, PTB-Braunschweig
|
| Quelle/Jahr | (2017), 114 S. |
| Dissertationsvermerk | Dissertation, Universität Hannover, 2017 |
| URL | |
| Verlag | Hannover: |
| Freie Schlagworte | ultracold calcium atoms and molecules ; one and two-color ph otoasso- ciation spectroscopy ; molecular ground-state potential ; optical Feshbach resonances ; scattering length |
| Zusammenfassung | In the first part of this thesis the measurement of the high power broadening of the ultra narrow transition 1S0-3P1 to photoassociated calcium molecules is presented. The validity of the resonant scattering theory was investigated for the description of these photoassociation spectra. The stimulated rates for these molecular transitions are determined by means of a coupled channel model. The stimulated rates and corresponding two-body loss rates in dependency of the laser intensity and the temperature of the atomic cloud derived from the experiment are compared with the theoretical values. The feasibility of low loss optical Feshach resonances for further scientific applications was investigated. The second part of the thesis focuses on the measurement of four most weakly bound molecular rovibrational states in the ground state X1Σ+g of calcium via two-color photoassociation spectroscopy. Using the measured binding energies the long range dispersion coefficients C6, C8, C10 including retardation at long nuclear distances were determined enabling the complete description of the ground state potential. The radiative transitions from the excited vibrational states in the molecular potentials Ω = 0 and Ω = 1 of the 3P1+1S0 asymptote to the ro-vibrational states in the molecular ground potential X1Σ+g were calculated. Based on these calculated values the effective production of ultracold Ca2 molecules in the desired ground state by spontaneous decay of excited molecules was predicted. The improved ground state potential allowed the calculation of the precise value of the s-wave scatterin g length improving its uncertainty by a factor of more than 10. Additionally theoretical values of the scattering lengths for all homonuclear pairs of stable calcium were given and estimation for the feasibility of the creation of Bose-Einstein condensates with these isotopes were proposed. |
