Recombination and excitation of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mi mathvariant="normal">HeH</mml:mi></mml:mrow><mml:mrow><mml:mo>+</mml:mo></mml:mrow></mml:msup></mml:mrow></mml:math>

Yousif, F. B.; Mitchell, James B.

doi:10.1103/physreva.40.4318

Cited by 77 publications

(44 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Moorhead et al (1988);Liu et al (1997)). We incorporated HeH + into our chemical network using the reactions and rate coefficients from Roberge & Dalgarno (1982), with the exception of the He + + H reaction, for which we used the rate coefficient from Zygelman & Dalgarno (1990), and the HeH + + e − reaction, where we used the experimentally determined rate from Yousif & Mitchell (1989) (via Cecchi-Pestellini & Dalgarno (1993)). We also neglected photodissociation of HeH + , as our input SED from mocassin has negligible flux in the wavelength range beyond the Lyman limit relevant for the cross-section given by Roberge & Dalgarno (1982).…”

Section: Predicted Hehmentioning

confidence: 99%

Modelling the ArH+ emission from the Crab nebula

Priestley

Barlow

Viti

2017

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

We have performed combined photoionization and photodissociation region (PDR) modelling of a Crab Nebula filament subjected to the synchrotron radiation from the central pulsar wind nebula, and to a high flux of charged particles; a greatly enhanced cosmic ray ionization rate over the standard interstellar value, ζ 0 , is required to account for the lack of detected [C I] emission in published Herschel SPIRE FTS observations of the Crab Nebula. The observed line surface brightness ratios of the OH + and ArH + transitions seen in the SPIRE FTS frequency range can only be explained with both a high cosmic ray ionization rate and a reduced ArH + dissociative recombination rate compared to that used by previous authors, although consistent with experimental upper limits. We find that the ArH + /OH + line strengths and the observed H 2 vibration-rotation emission can be reproduced by model filaments with n H = 2 × 10 4 cm −3 , ζ = 10 7 ζ 0 and visual extinctions within the range found for dusty globules in the Crab Nebula, although far-infrared emission from [O I] and [C II] is higher than the observational constraints. Models with n H = 1900 cm −3 underpredict the H 2 surface brightness, but agree with the ArH + and OH + surface brightnesses and predict [O I] and [C II] line ratios consistent with observations. These models predict HeH + rotational emission above detection thresholds, but consideration of the formation timescale suggests that the abundance of this molecule in the Crab Nebula should be lower than the equilibrium values obtained in our analysis.

show abstract

Section: Predicted Hehmentioning

confidence: 99%

Modelling the ArH+ emission from the Crab nebula

Priestley

Barlow

Viti

2017

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

show abstract

“…Furthermore, the relative simplicity of the system helps to gauge new experimental setups while also serving as a benchmark for different theoretical models. For these reasons, the low-energy collision process between electrons and the HeH + cations has attracted experimental interest [2][3][4][5][6][7][8][9] and theoretical studies [3,[10][11][12][13][14][15] over the past three decades.…”

Section: Introductionmentioning

confidence: 99%

Inelastic low-energy collisions of electrons with HeH+: Rovibrational excitation and dissociative recombination

Čurík

Greene

2017

The Journal of Chemical Physics

View full text Add to dashboard Cite

Inelastic low-energy (0-1 eV) collisions of electrons with HeH + cations are treated theoretically, with a focus on the rovibrational excitation and dissociative recombination (DR) channels. In an application of ab initio multichannel quantum defect theory (MQDT), the description of both processes is based on the Born-Oppenheimer quantum defects. The quantum defects were determined using the R-matrix approach in two different frames of reference:the center-of-charge and the center-of-mass frames. The results obtained in the two reference systems, after implementing the Fano-Jungen style rovibrational frame-transformation technique, shows differences in the rate of convergence for these two different frames of reference.We find good agreement with the available theoretically predicted rotationally inelastic thermal rate coefficients. Our computed DR rate also agrees well with available experimental results. Moreover, several computational experiments shed light on the role of rotational and vibrational excitations in the indirect DR mechanism that governs the low energy HeH + dissociation process. While the rotational excitation is several orders of magnitude more probable process at the studied collision energies, the closed-channel resonances described by the high-n, rotationally excited neutral molecules of HeH contribute very little to the dissociation probability. But the situation is very different for resonances defined by the high-n, vibrationally excited HeH molecules, which are found to dissociate with approximately 90%

show abstract

“…In this case, the incident electron causes a transition to a dissociative excited state of the target ion with enough internal energy to cause fragmentation [1][2][3] HeH + (v i , J i ) + e − → He + + H + e − .…”

Section: Introductionmentioning

confidence: 99%

Studies of HeH: DR, RIP, VE, DE, PI, MN, …

Larson

Nkambule

Ertan

et al. 2015

EPJ Web of Conferences

View full text Add to dashboard Cite

Abstract. The resonant states of HeH are computed by combining structure calculations at a full configuration interaction level with electron scattering calculations carried out using the Complex-Kohn variational method. We obtain the potential energy curves, autoionization widths, as well as non-adiabatic couplings among the resonant states. Using the non-adiabatic couplings, the adiabatic to diabatic transformation matrix can be obtained. A strict diabatization of the resonant states will be used to study various scattering processes where the resonant states are involved. These processes involve high energy dissociative recombination (DR) and ion-pair formation (RIP), resonant and direct dissociative excitation (DE), penning ionization (PI) as well as mutual neutralization (MN).

show abstract

Recombination and excitation ofHeH+

Cited by 77 publications

References 12 publications

Modelling the ArH+ emission from the Crab nebula

Modelling the ArH+ emission from the Crab nebula

Inelastic low-energy collisions of electrons with HeH+: Rovibrational excitation and dissociative recombination

Studies of HeH: DR, RIP, VE, DE, PI, MN, …

Contact Info

Product

Resources

About