The relativistic and nonrelativistic approaches for the calculations of the two-photon decay rates of highly excited states in hydrogen are compared. The dependence on the principal quantum number ( n ) of the n s, n d and n p initial states is investigated up to n = 100 for the nonresonant emissions. For the n s states together with the main E1E1 channel the contributions of higher multipoles (M1M1, E2E2 and E1M2) are considered. For the n p states the E1M1 and E1E2 channels are evaluated. Moreover, the simple analytical formula for the E1M1 decay is derived in the nonrelativistic limit.The relativistic and nonrelativistic approaches for the calculations of the two-photon decay rates of highly excited states in hydrogen are compared. The dependence on the principal quantum number ( n ) of the n s, n d and n p initial states is investigated up to n = 100 for the nonresonant emissions. For the n s states together with the main E1E1 channel the contributions of higher multipoles (M1M1, E2E2 and E1M2) are considered. For the n p states the E1M1 and E1E2 channels are evaluated. Moreover, the simple analytical formula for the E1M1 decay is derived in the nonrelativistic limit.

arXiv:1002.4743Journal of Physics B Atomic Molecular and Optical PhysicsAug 20, 20106 citations

High-precision measurement of lifetimes and collisional decay parameters in Ca D1 states using the two-photon Hanle effect

L. R. Hunter, G. M. Watson, David S. Weiss +1 more

We report high-precision measurements of the lifetimes and collisional decay parameters of the (4 ${p}^{2}$ ) ${\mathrm{}}^{1}$ D and (4s5d) ${\mathrm{}}^{1}$ D states of atomic calcium using the two-photon Hanle effect. Modification of the excited-state decay rates due to saturation of the two-photon transition is clearly observed. Spontaneous-emission rates of the possible dipole transitions from these states are deduced through branching-ratio measurements and compared with theory. The (4s4d ${)\mathrm{}}^{1}$ D lifetime is determined through observation of its exponential decay.We report high-precision measurements of the lifetimes and collisional decay parameters of the (4${p}^{2}$) ${\mathrm{}}^{1}$D and (4s5d) ${\mathrm{}}^{1}$D states of atomic calcium using the two-photon Hanle effect. Modification of the excited-state decay rates due to saturation of the two-photon transition is clearly observed. Spontaneous-emission rates of the possible dipole transitions from these states are deduced through branching-ratio measurements and compared with theory. The (4s4d${)\mathrm{}}^{1}$D lifetime is determined through observation of its exponential decay.

Physical Review AApr 1, 198520 citations

One-photon decay of two-hole states in atoms

M. Ya. Amus’ya, I. S. Li

Journal of Experimental and Theoretical PhysicsAug 1, 19770 citations

Resonant Two-Photon Transitions

Pavel A Apanasevich, G. I. Timofeeva

Journal of Applied SpectroscopyMay 1, 20184 citations

Virtual resonant states in two-photon decay processes: Lower-order terms, subtractions, and physical interpretations

Ulrich D. Jentschura

We investigate the two-photon decay rate of a highly excited atomic state which can decay to bound states of lower energy via cascade processes. We show that a na\"{\i}ve treatment of the process, based on the introduction of phenomenological decay rates for the intermediate, resonant states, leads to lower-order terms which need to be subtracted in order to obtain the coherent two-photon correction to the decay rate. The sum of the lower-order terms is exactly equal to the one-photon decay rate of the initial state, provided the na\"{\i}ve two-photon decay rates are summed over all available two-photon channels. A quantum electrodynamics treatment of the problem leads to an ``automatic'' subtraction of the lower-order terms.We investigate the two-photon decay rate of a highly excited atomic state which can decay to bound states of lower energy via cascade processes. We show that a na\"{\i}ve treatment of the process, based on the introduction of phenomenological decay rates for the intermediate, resonant states, leads to lower-order terms which need to be subtracted in order to obtain the coherent two-photon correction to the decay rate. The sum of the lower-order terms is exactly equal to the one-photon decay rate of the initial state, provided the na\"{\i}ve two-photon decay rates are summed over all available two-photon channels. A quantum electrodynamics treatment of the problem leads to an ``automatic'' subtraction of the lower-order terms.

arXiv:0810.0073Physical Review AFeb 19, 200925 citations

We report high-precision measurements of the lifetimes and collisional decay parameters of the (4

{p}^{2}

)

{\mathrm{}}^{1}

D and (4s5d)

{\mathrm{}}^{1}

D states of atomic calcium using the two-photon Hanle effect. Modification of the excited-state decay rates due to saturation of the two-photon transition is clearly observed. Spontaneous-emission rates of the possible dipole transitions from these states are deduced through branching-ratio measurements and compared with theory. The (4s4d

{)\mathrm{}}^{1}

D lifetime is determined through observation of its exponential decay.