Electronic structure of NH<sup>+</sup>: An ab initio study

Amero, J. M.; Vázquez, Gerardo J.

doi:10.1002/qua.20377

Cited by 21 publications

(31 citation statements)

References 40 publications

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“…The vibrational v levels of the NH + X 2 Π and a 4 Σ − states can also play a role. The level spacing for these two vibrational series is approximately 0.38 eV and 0.33 eV, respectively (Amero & Vázquez 2005). The next higher lying NH + bound electronic states are the A 2 Σ − , B 2 ∆, and C 2 Σ + .…”

Section: Dr Pathways For Nh +mentioning

confidence: 92%

DISSOCIATIVE RECOMBINATION MEASUREMENTS OF NH⁺USING AN ION STORAGE RING

Novotný

Berg

Bing

et al. 2014

ApJ

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We have investigated dissociative recombination (DR) of NH + with electrons using a merged beams configuration at the TSR heavy-ion storage ring located at the Max Planck Institute for Nuclear Physics in Heidelberg, Germany. We present our measured absolute merged beams recombination rate coefficient for collision energies from 0 to 12 eV. From these data we have extracted a cross section which we have transformed to a plasma rate coefficient for the collisional plasma temperature range from T pl = 10 to 18000 K. We show that the NH + DR rate coefficient data in current astrochemical models are underestimated by up to a factor of ∼ 9. Our new data will result in predicted NH + abundances lower than calculated by present models. This is in agreement with the sensitivity limits of all observations attempting to detect NH + in interstellar clouds.In the cold ISM, such as in molecular clouds, the most abundant nitrogen-bearing species are expected to be N and N 2 (Langer & Graedel 1989). However, direct observation of these is difficult. Atomic N does not have any low-lying, fine-structure levels that can be populated at molecular cloud temperatures and N 2 lacks a dipole moment, which is needed to provide reasonably strong ro-vibrational transitions. Thus, observations of tracers such as NH, NH 2 , NH 3 , or N 2 H + must be used to infer the N and N 2 abundances through chemical models.Neutral nitrogen hydrides are widely seen in the ISM. Ammonia (NH 3 ) was first detected by Cheung et al. (1968). Later NH 2 and NH were identified by van Dishoeck et al. (1993) and Meyer & Roth (1991), respectively. The observed abundances, however, do not match predictions from astrochemical models. In diffuse interstellar clouds, observed abundance ratio for NH/NH 3 are ∼ 1.7 and for NH 3 /H ∼ 3.2 × 10 −9 . These cannot be simultaneously explained by existing chemical models. The models can fit either one of the observed values but then the other predicted ratio is a factor of 10 off from the observation (Persson et al. 2010). Similarly, in dark clouds the abundance ratio for NH/NH 3 is underpredicted by more than an order of magnitude (Hily-Blant et al. 2010). These discrepancies possibly originate from using incorrect reaction rate coefficients in the models.

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Section: Dr Pathways For Nh +mentioning

confidence: 92%

DISSOCIATIVE RECOMBINATION MEASUREMENTS OF NH⁺USING AN ION STORAGE RING

Novotný

Berg

Bing

et al. 2014

ApJ

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“…The NH + cation has two close lying nearly degenerate terms 31,32 that both result in an absorption signal from our ion beam: 1s 2 2s 2 3s 2 1p 1 2 P and 1s 2 2s 2 3s 1 1p 2 4 S À .…”

Section: Molecular Target Nh +mentioning

confidence: 99%

Inner-shell X-ray absorption spectra of the cationic series NH_y⁺ (y = 0–3)

Bari

Inhester

Schubert

et al. 2019

Phys. Chem. Chem. Phys.

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“…Figure 1 gives an overview of the calculated singly excited potential energy curves of the ion (NH + ) as well as some singly and doubly excited curves for the neutral (NH). For this schematic overview, graphical representations of calculated potential curves of NH + [9] and NH [10] were overlaid assuming the adiabatic ionization energy of NH as given in [9]. The energy accuracy in this scheme is estimated to be at the ±0.1 eV level, sufficient for our considerations here.…”

mentioning

confidence: 99%