Rates of blackbody radiation-induced transitions from Rydberg states of alkali atoms

Abstract

General properties are considered of three different terms in the imaginary part of the Stark effect on nS, nP and nD Rydberg states of alkali atoms in the field of environmental blackbody radiation with temperature in the ranges between T = 100 K and T = 3000 K. The terms are equal to the rates of decay P d nl (T ), excitation P e nl (T ) and ionization P ion nl (T ) and may be separated and determined independently of each other. Corresponding numerical data calculated together with the rates of spontaneous decay P sp nl in the region of principal quantum numbers n from n = 10-1000 are transformed into fractional rates R d(e,ion) nl (T ) = P d(e,ion) nl (T )/P sp nl . The asymptotic dependences on T and n display an essential difference between the fractional rates of ionization R ion nl (T ) ∝ T n 2/3 and the rates of decay (excitation) R d(e) nl (T ) ∝ T n, approximated by two different asymptotic formulae, one for R ion nl (T ) and another one for R d(e)nl (T ). The approximation polynomials with coefficients, determined from the curve-fitting polynomial interpolation procedure for three values of n between n = 15 and n = 150 at three values of temperature T = 100, 300, 1000 K, reproduce the calculated values with fractional departures below 2-3% in the regions from n = 10 to n = 1000 at temperatures from T = 100 K to T = 3000 K.

Precision measurement of the ionization energy of Cs i

“…Possible contributions to the widths are the spontaneous decay of the Rydberg states, the Doppler broadening of the transitions, inhomogeneous broadening caused by residual electric fields, broadenings induced by Rydberg-Rydberg-interactions, the hyperfine splitting of the Rydberg states, and the bandwidth of the excitation radiation. The natural line widths of transitions to np Rydberg states scale with the principal quantum number n approximately as n −3 and are less than 10 kHz for n ≥ 27 [36]. Their contributions to the experimental line widths are thus negligible.…”

Imaging the evolution of an ultracold strontium Rydberg gas

“…However, because this growth is slow, other processes must be considered that might contribute to the growth in the number of visible ion cores after 1 D 2 excitations, such as population redistribution to states with attractive potentials by blackbody radiation (BBR) and BBRinduced photoionization. Calculations for hydrogen, helium, and the alkali metals [73][74][75] suggest that while the rates for excitation/deexcitation of Rydberg states by BBR depend on the particular atomic species, the rate for states with n ∼ 50 should be less than ∼1 × 10 4 s −1 . Whereas such rates might allow up to 10% of the parent 1 D 2 Rydberg states to undergo a transition to states of different ℓ on the time scale (∼10 µs) of the present measurements, this is insufficient to significantly increase the overall transition rate.…”

Observation of Dipole-Quadrupole Interaction in an Ultracold Gas of Rydberg Atoms

“…3 a)) and ultracold temperatures, ∆E rot,max is always smaller than the linewidth of the pair states (approximated by the sum of atomic linewidths from Ref. [29]) and therefore the rotational states of opposite parity can be considered as degenerate. We therefore assume the coupling between electronic and rotational motion to be the same for interaction terms which require a change in L (i.e., dipole-quadrupole) as for terms which do not require a change in L (i.e., dipole-dipole and quadrupolequadrupole).…”