Some ion chemistry of HC5N

Edwards, Samuel J.; Freeman, Colin G.; McEwan, Murray J.

doi:10.1016/j.ijms.2008.10.003

Cited by 13 publications

(9 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The next larger members in the series of cyanopolyynes and dicyanopolyynes are also good candidates to be detected in their protonated form. Cyanodiacetylene (HC 5 N) has a high proton affinity (770 ± 20 kJ mol −1 ; Edwards et al 2009) and it is just a few times less abundant than HC 3 N in cold dark cores (Agúndez & Wakelam 2013). Dicyanoacetylene (NC 4 N) also has a high proton affinity (736 kJ mol −1 ; this work) and it is likely to be present with a high abundance based on the large inferred abundance of NCCN.…”

Section: Introductionmentioning

confidence: 85%

“…A large proton affinity permits the transfer of H + to the neutral species, M, through the reactions M + XH + → MH + + X, where XH + is an abundant proton donor, such as HCO + or H + 3 . For cyanodiacetylene, HC 5 N, the proton affinity was measured to be 770 ± 20 kJ mol −1 (Edwards et al 2009). The abundance of this species is large in cold dark cores, hence, we could expect a moderately high abundance for its protonated form.…”

Section: Assignment To Hc 5 Nh + and Derived Column Densitymentioning

confidence: 95%

See 1 more Smart Citation

Tentative detection of HC₅NH⁺ in TMC-1

Marcelino

Agúndez

Tercero

et al. 2020

A&A

View full text Add to dashboard Cite

Using the Yebes 40m radio telescope, we report the detection of a series of seven lines harmonically related with a rotational constant B0 = 1295.81581 ± 0.00026MHz and a distortion constant D0 = 27.3 ± 0.5Hz towards the cold dense cloud TMC-1. Ab initio calculations indicate that the best possible candidates are the cations HC5NH+ and NC4NH+. From a comparison between calculated and observed rotational constants and other arguments based on proton affinities and dipole moments, we conclude that the best candidate for a carrier of the observed lines is the protonated cyanodiacetylene cation, HC5NH+. The HC5N/HC5NH+ ratio derived in TMC-1 is 240, which is very similar to the HC3N/HC3NH+ ratio. Results are discussed in the framework of a chemical model for protonated molecules in cold dense clouds.

show abstract

Section: Introductionmentioning

confidence: 85%

Section: Assignment To Hc 5 Nh + and Derived Column Densitymentioning

confidence: 95%

Tentative detection of HC₅NH⁺ in TMC-1

Marcelino

Agúndez

Tercero

et al. 2020

A&A

View full text Add to dashboard Cite

show abstract

“…New relevant data that have been obtained since 2007 can be found in Edwards et al (2008in Edwards et al ( , 2009, Fondren et al ( 2009), Gerlich and Borodi ( 2009 2013) and Lin et al (2013). They represent about 170 reactions.…”

Section: Reaction Class Chemical Equation Neutral Speciesmentioning

confidence: 97%

Simulating the density of organic species in the atmosphere of Titan with a coupled ion-neutral photochemical model

Vuitton

Yelle

Klippenstein

et al. 2019

Icarus

167

362

View full text Add to dashboard Cite

We present a one-dimensional coupled ion-neutral photochemical kinetics and diffusion model to study the atmospheric composition of Titan in light of new theoretical kinetics calculations and scientific findings from the Cassini-Huygens mission. The model extends from the surface to the exobase. The atmospheric background, boundary conditions, vertical transport and aerosol opacity are all constrained by the Cassini-Huygens observations. The chemical network includes reactions between hydrocarbons, nitrogen and oxygen bearing species. It takes into account neutrals and both positive and negative ions with masses extending up to about 100 u. We incorporate high-resolution isotopic photoabsorption and photodissociation cross sections for N 2 as well as new photodissociation branching ratios for CH 4 and C 2 H 2 . Ab initio transition state theory calculations are performed in order to estimate the rate coefficients and products for critical reactions.Main reactions of production and loss for neutrals and ions are quantitatively assessed and thoroughly discussed. The vertical distributions of neutrals and ions predicted by the model generally reproduce observational data, suggesting that for the small species most chemical processes in Titan's atmosphere and ionosphere are adequately described and understood; some differences are highlighted. Notable remaining issues include (i) the total positive ion density (essentially HCNH + ) in the upper ionosphere, (ii) the low mass negative ion densities (CN -, C 3 N -/C 4 H -) in the upper atmosphere, and (iii) the minor oxygen-bearing species (CO 2 , H 2 O) density in the stratosphere. Pathways towards complex molecules and the impact of aerosols (UV shielding, atomic and molecular hydrogen budget, nitriles heterogeneous chemistry and condensation) are evaluated in the model, along with lifetimes and solar cycle variations.

show abstract

“…The proton affinities of the nitriles whose protonated species have been detected in TMC-1 are between 674.7 kJ mol −1 (for NCCN; Hunter & Lias 1998) and 770 ± 20 kJ mol −1 (for HC 5 N; Edwards et al 2009). These values are larger than the proton affinities of molecules such as CO or N 2 and smaller than those of C 3 O or C 3 S. For cyanopolyynes, the longer the carbon chain, the higher the proton affinity.…”

Section: Introductionmentioning

confidence: 99%

Discovery of a new molecular ion, HC7NH+, in TMC-1

Cabezas,

Agundez,

Marcelino

et al. 2022

Preprint

View full text Add to dashboard Cite

We report the detection of the protonated form of HC 7 N in TMC-1. The discovery of the cation HC 7 NH + was carried out via the observation of nine harmonically related lines in the Q-band using the Yebes 40m radiotelescope. The observed frequencies allowed us to obtain the rotational constants B 0 =553.938802(160) MHz and D 0 =3.6292(705) Hz. The identification of HC 7 NH + is further supported by accurate ab initio calculations. We derived a column density of (5.5±0.7)×10 10 cm −2 , which constitutes another piece of evidence for the identification of the carrier. In addition, we revised the HC 7 N column density and we derived a new value of (2.1±0.2)×10 13 cm −2 . Hence, the abundance ratio HC 7 N/HC 7 NH + is ∼380, while those for HC 3 N/HC 3 NH + and HC 5 N/HC 5 NH + are ∼230 and ∼240, respectively. Here, we discuss these results within the framework of a chemical model for protonated molecules in cold dense clouds.

show abstract

Some ion chemistry of HC5N

Cited by 13 publications

References 25 publications

Tentative detection of HC₅NH⁺ in TMC-1

Tentative detection of HC₅NH⁺ in TMC-1

Simulating the density of organic species in the atmosphere of Titan with a coupled ion-neutral photochemical model

Discovery of a new molecular ion, HC7NH+, in TMC-1

Contact Info

Product

Resources

About

Some ion chemistry of HC5N

Cited by 13 publications

References 25 publications

Tentative detection of HC5NH+ in TMC-1

Tentative detection of HC5NH+ in TMC-1

Simulating the density of organic species in the atmosphere of Titan with a coupled ion-neutral photochemical model

Discovery of a new molecular ion, HC7NH+, in TMC-1

Contact Info

Product

Resources

About

Tentative detection of HC₅NH⁺ in TMC-1

Tentative detection of HC₅NH⁺ in TMC-1