Decay Dynamics of High Rydberg States in Atoms and Molecules: Discussion

N_{2} molecules traveling in pulsed supersonic beams have been excited from their X ^{1}Σ_{g}^{+} ground electronic state to long-lived Rydberg states with principal quantum numbers between 39 and 48 using a resonance-enhanced two-color three-photon excitation scheme. The Rydberg states populated had static electric dipole moments exceeding 5000 D which allowed deceleration of the molecules to rest in the laboratory-fixed frame of reference and three-dimensional trapping using inhomogeneous electric fields. The trapped molecules were confined for up to 10 ms, with effective trap decay time constants increasing with principal quantum number, and ranging from 450 to 700 μs. These observations, and comparison with the results of similar measurements with He atoms, indicate that the decay dynamics of the trapped Rydberg N_{2} molecules are dominated by spontaneous emission and do not exhibit significant contributions from effects of intramolecular interactions that lead to non-radiative decay.N_{2} molecules traveling in pulsed supersonic beams have been excited from their X ^{1}Σ_{g}^{+} ground electronic state to long-lived Rydberg states with principal quantum numbers between 39 and 48 using a resonance-enhanced two-color three-photon excitation scheme. The Rydberg states populated had static electric dipole moments exceeding 5000 D which allowed deceleration of the molecules to rest in the laboratory-fixed frame of reference and three-dimensional trapping using inhomogeneous electric fields. The trapped molecules were confined for up to 10 ms, with effective trap decay time constants increasing with principal quantum number, and ranging from 450 to 700 μs. These observations, and comparison with the results of similar measurements with He atoms, indicate that the decay dynamics of the trapped Rydberg N_{2} molecules are dominated by spontaneous emission and do not exhibit significant contributions from effects of intramolecular interactions that lead to non-radiative decay.

arXiv:2403.12315Physical Review LettersMar 12, 20244 citations

SELECTIVE POPULATION OF MOLECULAR CORE NONPENETRATING RYDBERG STATES

David Grimes, Robert W. Field, Ethan Klein +2 more

"Core nonpenetrating Rydberg states of molecules are a neglected state of matter. They could have a variety of uses, notably state-selective production of molecular ions. Due to the \textit{l}(\textit{l}+1)/r $^{2}$ centrifugal barrier that prevents the Rydberg electron in high-\textit{l} states from penetrating inside of the ion core, the electron is essentially uncoupled from the ion core, and the system becomes atom-like with long lifetimes, an ""almost good"" \textit{l} quantum number, and electronic transitions that follow $\Delta$ J $^{+}$ =0 and $\Delta$ v $^{+}$ =0 propensity rules. However, in most molecules access to these states, via a sequence of $\Delta$ \textit{l}=+1 transitions from low-n*, low-\textit{l} states, is blocked by the necessity to traverse the ""zone of death,"" in which nonradiative decay mechanisms are prohibitively fast. We exploit Chirped Pulse millimeter-Wave (CPmmW) spectroscopy to efficiently excite Ca atoms and BaF molecules to core nonpenetrating states in the absence of nonradiative decay mechanisms. A universal method for preparing core nonpenetrating Rydberg states of molecules, which combines CPmmW spectroscopy with STImulated Raman Adiabatic Passage (STIRAP), will be discussed.""Core nonpenetrating Rydberg states of molecules are a neglected state of matter. They could have a variety of uses, notably state-selective production of molecular ions. Due to the \textit{l}(\textit{l}+1)/r$^{2}$ centrifugal barrier that prevents the Rydberg electron in high-\textit{l} states from penetrating inside of the ion core, the electron is essentially uncoupled from the ion core, and the system becomes atom-like with long lifetimes, an ""almost good"" \textit{l} quantum number, and electronic transitions that follow $\Delta$J$^{+}$=0 and $\Delta$v$^{+}$=0 propensity rules. However, in most molecules access to these states, via a sequence of $\Delta$\textit{l}=+1 transitions from low-n*, low-\textit{l} states, is blocked by the necessity to traverse the ""zone of death,"" in which nonradiative decay mechanisms are prohibitively fast. We exploit Chirped Pulse millimeter-Wave (CPmmW) spectroscopy to efficiently excite Ca atoms and BaF molecules to core nonpenetrating states in the absence of nonradiative decay mechanisms. A universal method for preparing core nonpenetrating Rydberg states of molecules, which combines CPmmW spectroscopy with STImulated Raman Adiabatic Passage (STIRAP), will be discussed."

International Symposium on Molecular Spectroscopy (ISMS)Jun 19, 20140 citations

Dynamic processes in molecular rydberg states

Hanspeter Helm

Springer eBooksApr 6, 20081 citation

Dissociation of ultracold cesium Rydberg-ground molecules

Jingxu Bai, Yuechun Jiao, Rong Song +3 more

We report the experimental measurements of the decay rate of polar cesium nD5/2 - 6S1/2 Rydberg-ground molecules with a large principal quantum number range of 35 ≤ n ≤ 40. Rydberg molecules are prepared employing the method of two-photon photoassociation and the molecular (atomic) ions, due to autoionization (blackbody photoionization), are detected with a microchannel plate detector. The decay rate Γ of the vibrational ground state of the deep and shadow bound molecules for triplet (TΣ) and mixed singlet-triplet (S,TΣ) are measured by fitting the molecular population with the exponential function. Comparing with the parent atom, the decay rate of the polar Rydberg-ground molecule shows an obvious increase with a magnitude of a few μs. The possible dissociation mechanism of polar Rydberg-ground molecules including a collisional decay, blackbody induced decay, and coupling of adjacent Rydberg states and tunneling decay are discussed in detail. The theoretical model is induced to simulate the measurements, showing agreement.We report the experimental measurements of the decay rate of polar cesium nD5/2 - 6S1/2 Rydberg-ground molecules with a large principal quantum number range of 35 ≤ n ≤ 40. Rydberg molecules are prepared employing the method of two-photon photoassociation and the molecular (atomic) ions, due to autoionization (blackbody photoionization), are detected with a microchannel plate detector. The decay rate Γ of the vibrational ground state of the deep and shadow bound molecules for triplet (TΣ) and mixed singlet-triplet (S,TΣ) are measured by fitting the molecular population with the exponential function. Comparing with the parent atom, the decay rate of the polar Rydberg-ground molecule shows an obvious increase with a magnitude of a few μs. The possible dissociation mechanism of polar Rydberg-ground molecules including a collisional decay, blackbody induced decay, and coupling of adjacent Rydberg states and tunneling decay are discussed in detail. The theoretical model is induced to simulate the measurements, showing agreement.

The Journal of Chemical PhysicsNov 15, 20232 citations

Advances in Physics of Rydberg Atoms and Molecules

Eugene Oks

Institute of Physics eBooksNov 1, 20214 citations

^{2}

centrifugal barrier that prevents the Rydberg electron in high-\textit{l} states from penetrating inside of the ion core, the electron is essentially uncoupled from the ion core, and the system becomes atom-like with long lifetimes, an ""almost good"" \textit{l} quantum number, and electronic transitions that follow

\Delta

^{+}

=0 and

\Delta

^{+}

=0 propensity rules. However, in most molecules access to these states, via a sequence of

\Delta

\textit{l}=+1 transitions from low-n*, low-\textit{l} states, is blocked by the necessity to traverse the ""zone of death,"" in which nonradiative decay mechanisms are prohibitively fast. We exploit Chirped Pulse millimeter-Wave (CPmmW) spectroscopy to efficiently excite Ca atoms and BaF molecules to core nonpenetrating states in the absence of nonradiative decay mechanisms. A universal method for preparing core nonpenetrating Rydberg states of molecules, which combines CPmmW spectroscopy with STImulated Raman Adiabatic Passage (STIRAP), will be discussed."