Relaxation and frequency shifts in the ground state of Rb⁸⁵

Relaxation rates and frequency shifts of the 0-0 hyperfine transition in the ground state of Rb⁸⁵ are studied in some detail at 3.03 GHz. Results on the relaxation rates of the populations and of the coherence introduced in the system by a short microwave pulse are given. Physical parameters are extracted from the data and are interpreted in terms of wall interactions, buffer-gas interactions, and spin-exchange interactions. The data are analyzed in terms of simple theoretical models and are also discussed in relation to published results on other isotopes or alkali-metal atoms.