Dipole moments of HCO<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msup><mml:mrow /><mml:mo>+</mml:mo></mml:msup></mml:math>and NH<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msup><mml:mrow /><mml:mo>+</mml:mo></mml:msup></mml:math>from cyclotron frequency polarizability shifts

Mount, B. J.; Redshaw, Matthew; Myers, E. G.

doi:10.1103/physreva.85.012519

Cited by 15 publications

(13 citation statements)

References 24 publications

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“…The Penning trap has a number of advantages for some kinds of experiments. It is the ideal tool for precision measurements on ions that require a large magnetic field, for example, the measurement of the bound-state electron g -factor19 or the measurement of dipole moments of molecular ions from shifts to the cyclotron frequency due to their polarizability20. However, it may also have some advantages for certain proposed experiments with ICCs where the interest lies in the sensitive dynamics of the transitions between different crystal conformations that occur when the trapping potential is varied1121.…”

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confidence: 99%

Control of the conformations of ion Coulomb crystals in a Penning trap

et al. 2013

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Laser-cooled atomic ions form ordered structures in radiofrequency ion traps and in Penning traps. Here we demonstrate in a Penning trap the creation and manipulation of a wide variety of ion Coulomb crystals formed from small numbers of ions. The configuration can be changed from a linear string, through intermediate geometries, to a planar structure. The transition from a linear string to a zigzag geometry is observed for the first time in a Penning trap. The conformations of the crystals are set by the applied trap potential and the laser parameters, and agree with simulations. These simulations indicate that the rotation frequency of a small crystal is mainly determined by the laser parameters, independent of the number of ions and the axial confinement strength. This system has potential applications for quantum simulation, quantum information processing and tests of fundamental physics models from quantum field theory to cosmology.

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confidence: 99%

Control of the conformations of ion Coulomb crystals in a Penning trap

et al. 2013

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“…1). The Einstein A values (Tables D.1−D.2) were derived by one of us (HSPM) from these data, using the experimental ground-state electric dipole moment of 1.988 (28) D (Mount et al 2012), and taking additional parameters from Hübers et al (2009) into account. The frequency of the…”

Section: Spectroscopy Observations and Data Reductionmentioning

confidence: 99%

Upper limits to interstellar NH⁺and para-NH₂⁻abundances

Persson

Hajigholi

Hassel

et al. 2014

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The understanding of interstellar nitrogen chemistry has improved significantly with recent results from the Herschel Space Observatory. To set even better constraints, we report here on deep searches for the NH + ground state rotational transition J = 1.5−0.5 of the 2 Π 1/2 lower spin ladder, with fine-structure transitions at 1013 and 1019 GHz, and the para-NH in the Sgr B2 (M) molecular envelope and in the G10.6−0.4 molecular cloud, respectively. The searches are, however, complicated by the fact that the 1 013 GHz transition lies only −2.5 km s −1 from a CH 2 NH line, which is seen in absorption in Sgr B2 (M), and that the hyperfine structure components in the 1019 GHz transition are spread over 134 km s −1 . Searches for the so far undetected NH − 2 anion turned out to be unfruitful towards G10.6−0.4, while the para-NH − 2 1 1,1 −0 0,0 transition was tentatively detected towards Sgr B2 (M) at a velocity of 19 km s −1 . Assuming that the absorption occurs at the nominal source velocity of +64 km s −1 , the rest frequency would be 933.996 GHz, offset by 141 MHz from our estimated value. Using this feature as an upper limit, we found N(p-NH − 2 ) < ∼ 4 × 10 11 cm −2 , which implies an abundance of < ∼ 8 × 10 −13 in the Sgr B2 (M) molecular envelope. The upper limits for both species in the diffuse line-of-sight gas are less than 0.1 to 2% of the values found for NH, NH 2 , and NH 3 towards both sources, and the abundance limits are < ∼ 2−4 × 10 −11 . An updated pseudo time-dependent chemical model with constant physical conditions, including both gas-phase and surface chemistry, predicts an NH + abundance a few times lower than our present upper limits in diffuse gas and under typical Sgr B2 (M) envelope conditions. The NH − 2 abundance is predicted to be several orders of magnitudes lower than our observed limits, hence not supporting our tentative detection. Thus, while NH − 2 may be very difficult to detect in interstellar space, it could, on the other hand, be possible to detect NH + in regions where the ionisation rates of H 2 and N are greatly enhanced.

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“…In particular, the data for H + 3 /HD + show that H + 3 (2) had 0.54(6) eV more internal energy than H + 3 (1); while the data for H + 3 / 3 He + show (2) had 0.25(6) eV more energy than (3a). H + 3 (3) then apparently lost 0.19 (7) eV between 6/27 (3a) and 8/8 (3b), but did not change significantly, 0.04(6) eV, after a further 10 weeks (3c).…”

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“…Precision measurements of cyclotron frequencies of single ions in a cryogenic Penning trap yield atomic mass ratios with application to fundamental constants and tests of fundamental physics [1][2][3]. Changes in cyclotron frequency have also been used to detect the rotational state of molecular ions with body-frame dipole moments due to their large polarizability [4][5][6][7]. In this Letter, we show sensitivity to the rotational state of a molecular ion simply through the change in inertial mass, and hence cyclotron frequency, due to the extra internal energy [8].…”

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Rotational Energy as Mass in H3+ and Lower Limits on the Atomic Masses of D and He<

et al. 2018

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We have made precise measurements of the cyclotron frequency ratios H_{3}^{+}/HD^{+} and H_{3}^{+}/^{3}He^{+} and observe that different H_{3}^{+} ions result in different cyclotron frequency ratios. We interpret these differences as due to the molecular rotational energy of H_{3}^{+} changing its inertial mass. We also confirm that certain high J, K rotational levels of H_{3}^{+} have mean lifetimes exceeding several weeks. From measurements with the lightest H_{3}^{+} ion we obtain lower limits on the atomic masses of deuterium and helium-3 with respect to the proton.

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Dipole moments of HCO+and NH+from cyclotron frequency polarizability shifts

Cited by 15 publications

References 24 publications

Control of the conformations of ion Coulomb crystals in a Penning trap

Control of the conformations of ion Coulomb crystals in a Penning trap

Upper limits to interstellar NH⁺and para-NH₂⁻abundances

Rotational Energy as Mass in H3+ and Lower Limits on the Atomic Masses of D and He<

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Dipole moments of HCO+and NH+from cyclotron frequency polarizability shifts

Cited by 15 publications

References 24 publications

Control of the conformations of ion Coulomb crystals in a Penning trap

Control of the conformations of ion Coulomb crystals in a Penning trap

Upper limits to interstellar NH+and para-NH2−abundances

Rotational Energy as Mass in H3+ and Lower Limits on the Atomic Masses of D and He<

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Upper limits to interstellar NH⁺and para-NH₂⁻abundances