
Physics 2008
Ionization of Rydberg atoms by blackbody radiationDOI: 10.1088/13672630/11/1/013052 Abstract: We have studied an ionization of alkalimetal Rydberg atoms by blackbody radiation (BBR). The results of the theoretical calculations of ionization rates of Li, Na, K, Rb and Cs Rydberg atoms are presented. Calculations have been performed for nS, nP and nD states which are commonly used in a variety of experiments, at principal quantum numbers n=865 and at the three ambient temperatures of 77, 300 and 600 K. A peculiarity of our calculations is that we take into account the contributions of BBRinduced redistribution of population between Rydberg states prior to photoionization and field ionization by extraction electric field pulses. The obtained results show that these phenomena affect both the magnitude of measured ionization rates and shapes of their dependences on n. A Cooper minimum for BBRinduced transitions between bound Rydberg states of Li has been found. The calculated ionization rates are compared with our earlier measurements of BBRinduced ionization rates of Na nS and nD Rydberg states with n=820 at 300 K. A good agreement for all states except nS with n>15 is observed. Useful analytical formulas for quick estimation of BBR ionization rates of Rydberg atoms are presented. Application of BBRinduced ionization signal to measurements of collisional ionization rates is demonstrated.
