Lifetimes of the negative molecular hydrogen ions:<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mmultiscripts><mml:mi mathvariant="normal">H</mml:mi><mml:mn>2</mml:mn><mml:none /><mml:none /><mml:mo>−</mml:mo></mml:mmultiscripts></mml:math>,<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mmultiscripts><mml:mi mathvariant="normal">D</mml:mi><mml:mn>2</mml:mn><mml:none /><mml:none /><mml:mo>−</mml:mo></mml:mmultiscripts></mml:math>, and<mml:math

Heber, O.; Golser, Robin; Gnaser, Hubert; Berkovits, D.; Toker, Yoni; Eritt, Markus; Rappaport, Michael; Zajfman, D.

doi:10.1103/physreva.73.060501

Cited by 29 publications

(14 citation statements)

References 22 publications

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“…5 Only odd-sized clusters were observed, consistently with the very short-lived nature of H − 2 (Ref. 17) and its existence mainly as a metastable intermediate. Among even-sized compounds, mass spectrometry reveals drops in abundances above sizes N of 25, 65, and, albeit to a slightly lesser extent, 89.…”

Section: H −supporting

confidence: 55%

The quantum structure of anionic hydrogen clusters

Calvo

Yurtsever

2017

The Journal of Chemical Physics

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A flexible and polarizable interatomic potential has been developed to model hydrogen clusters interacting with one hydrogen anion, (H)H, in a broad range of sizes n = 1-54 and parametrized against coupled cluster quantum chemical calculations. Using path-integral molecular dynamics simulations at 1 K initiated from the putative classical global minima, the equilibrium structures are found to generally rely on icosahedral shells with the hydrogen molecules pointing toward the anion, producing geometric magic numbers at sizes n = 12, 32, and 44 that are in agreement with recent mass spectrometry measurements. The energetic stability of the clusters is also connected with the extent of vibrational delocalization, measured here by the fluctuations among inherent structures hidden in the vibrational wave function. As the clusters grow, the outer molecules become increasingly free to rotate, and strong finite size effects are also found between magic numbers, associated with more prominent vibrational delocalization. The effective icosahedral structure of the 44-molecule cluster is found to originate from quantum nuclear effects as well, the classical structure showing no particular symmetry.

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Section: H −supporting

confidence: 55%

The quantum structure of anionic hydrogen clusters

Calvo

Yurtsever

2017

The Journal of Chemical Physics

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“…As in the case ofpH, with increasing the rotational quantum number J H 2 − , the autodetachment of H 2 − is expected to become inhibited. The theoretical calculation provided the lifetime τ H 2 − ∼ 0.3 μs (controlled by the tunneling through the centrifugal barrier) for the resonance with J H 2 − = 26 [55], while the experimental value was τ H 2 − 8.2 μs for the longlived species [56]. The reason for this discrepancy has not been explained in a precise sense [55].…”

Section: B H 2 −mentioning

confidence: 94%

Exotic molecules consisting of an antiproton and a hydrogen atom

Sakimoto

2018

Phys. Rev. A

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A theoretical study is conducted on the stability of exotic antiproton-hydrogen molecular anions (pH), which in the separated atom limit correlate withp + H(n = 2) (n being the principal quantum number). Thē pH molecule in the electronic ground state is highly unstable due to pair annihilation and autodetachment (→pp + e). However, if thepH molecule is electronically excited, the molecular stability can be drastically improved. Since the excited states of the H atom have accidental degeneracy, the asymptotic form of the Born-Oppenheimer potential curve ofp + H(n = 2) behaves as 1/R 2 (R being the relative distance), which can play a critical role in the bonding and stability of the molecule. It is found that thepH molecule in the first electronic excited state and in a high rotational state is sufficiently stable and has a lifetime dominated by spontaneous radiative emission (→p + H + hν). ThepH system is dynamically similar to H 2 − , which had been commonly considered to be unstable due to autodetachment. However, recent measurements of ion-beam sputtering unambiguously verified the existence of long-lived H 2 − molecules in high rotational states. This suggests that thepH molecules may actually be created if one employs experimental means such as the chemical sputtering of hydrogen-rich targets withp beams.

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“…Since intrabeam scattering reduces the number of ions in the bunch, this is expected to only affect the total bunch charge and not its length x. Substitution of equation (12) in the amplitude A of equation (8), therefore, yields the following formula to reproduce the observed bunch intensity at the second harmonic frequency as a function of time:…”

Section: Bunch Decay Modelmentioning

confidence: 99%

“…These traps only use electrostatic fields, functioning on a principle quite similar to that of an optical resonator. Numerous traps such as these have been built in recent years, hosting a wide variety of experiments in cluster physics [4][5][6][7][8][9][10], molecular physics [11][12][13] and electron collision studies [14]. Experiments probing larger clusters and other heavy species exploit the mass invariance of ion trajectories in these electrostatic storage devices.…”

Section: Introductionmentioning

confidence: 99%