C6H and C6D: Electronic spectra and Renner-Teller analysis

Haddad, Mohammad Ali; Linnartz, H.; Ubachs, Wim

doi:10.1063/1.3609112

Cited by 23 publications

(11 citation statements)

References 32 publications

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“…This reverse in orbital energy order leads to the fact that HCC and HC 4 have a 2 Σ + ground state, 48,49 while HC 6 and those longer have a 2 Π ground state. 50,51 Near the crossover, one encounters some very small state differences, which in turn lead to an excellent laboratory for studying the Renner–Teller effect. The molecules in question, HC n , n = 1–12, are of prime interest to the astrophysical community, as they have been observed in the interstellar medium.…”

Section: Extending the Carbon Chainmentioning

confidence: 99%

Tuning the Ground State Symmetry of Acetylenyl Radicals

et al. 2015

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The lowest excited state of the acetylenyl radical, HCC, is a 2Π state, only 0.46 eV above the ground state, 2Σ+. The promotion of an electron from a π bond pair to a singly occupied σ hybrid orbital is all that is involved, and so we set out to tune those orbital energies, and with them the relative energetics of 2Π and 2Σ+ states. A strategy of varying ligand electronegativity, employed in a previous study on substituted carbynes, RC, was useful, but proved more difficult to apply for substituted acetylenyl radicals, RCC. However, π-donor/acceptor substitution is effective in modifying the state energies. We are able to design molecules with 2Π ground states (NaOCC, H2NCC (2A″), HCSi, FCSi, etc.) and vary the 2Σ+–2Π energy gap over a 4 eV range. We find an inconsistency between bond order and bond dissociation energy measures of the bond strength in the Si-containing molecules; we provide an explanation through an analysis of the relevant potential energy curves.

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Section: Extending the Carbon Chainmentioning

confidence: 99%

Tuning the Ground State Symmetry of Acetylenyl Radicals

et al. 2015

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“…The experimental setup has been described in detail before. 28,30 Carbon-chain species are produced in a plasma source by discharging an acetylene/helium gas mixture in a pinhole discharge nozzle, which is specifically suitable for the study of larger carbonchain species. The precursor gas mixture is expanded with a backing pressure of ∼10 bar into a vacuum chamber that is pumped by a roots blower system with a total capacity of 1000 m 3 /hr.…”

Section: A Experimental Setupmentioning

confidence: 99%

The electronic spectrum of the C s-C11H3 radical

Zhao

Linnartz

Ubachs

2012

The Journal of Chemical Physics

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The electronic gas-phase absorption spectrum of the bent carbon-chain radical, HC(4)CHC(6)H with C(s) symmetry, is recorded in the 595 nm region by cavity ring-down spectroscopy through an expanding hydrogen plasma. An unambiguous spectroscopic identification becomes possible from a systematic deuterium labeling experiment. A comparison of the results with recently reported spectra of the nonlinear HC(4)CHC(4)H and HC(4)C(C(2)H)C(4)H radicals with C(2v) symmetry provides a more comprehensive understanding of the molecular behavior of π-conjugated bent carbon-chain systems upon electronic excitation. We find that the electronic excitation in the bent carbon-chain HC(4)CHC(2n)H (n = 1-4) series exhibits a similar trend as in the linear HC(2n+1)H (n = 3-6) series, shifting optical absorptions towards longer wavelengths for increasing overall bent chain lengths. The π-conjugation in bent HC(4)CHC(2n)H (n = 1-4) chains is found to be generally smaller than in the linear HC(2n+1)H (n = 3-6) case for equivalent numbers of C-atoms. The addition of an electron-donating group to the bent chain causes a slight decrease of the effective conjugation.

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“…Rotationally unresolved absorption features of the P and R branches of the B 2 P 3=2 -X 2 P 3=2 and B 2 P 3=2 -X 2 P 3=2 transitions can be identified clearly. The P and R branches of the 11 1 1 l 2 P Àl 2 P transition of C 6 H around 524.4 nm as well as an electronic transition of C 9 H 3 at $529.6 nm, 18,23 not apparent in the I oes spectrum, also become visible in the extracted absorption spectrum.…”

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confidence: 94%

“…A clear absorption is visible at $526.1 nm. By comparing the wavelength and spectral profiles to previous CRDS work with the same plasma source and similar discharge conditions, 18,21 the absorption spectrum can be assigned to the two spin-orbit components of the B 2 P-X 2 P electronic origin band transitions of the open shell carbon chain radical C 6 H. Using the calculated oscillator strength, 22 the C 6 H expansion densities are estimated to be $10 10 À 10 11 molecules/cm 3 . The experimental spectrum shown in Fig.…”

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confidence: 97%

Cavity enhanced plasma self-absorption spectroscopy

Walsh

Linnartz

2012

Appl. Phys. Lett.

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Simultaneous imaging electron-and ion-feature Thomson scattering measurements of radiatively heated Xe Rev. Sci. Instrum. 83, 10E348 (2012) A collinear self-emission and laser-backlighting imaging diagnostic Rev. Sci. Instrum. 83, 083507 (2012) Enhancements to the JET poloidally scanning vacuum ultraviolet/visible spectrometers Rev. Sci. Instrum. 83, 10D536 (2012) Thomson scattering in short pulse laser experiments Phys. Plasmas 19, 083302 (2012)Additional information on Appl. Phys. Lett.

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C6H and C6D: Electronic spectra and Renner-Teller analysis

Cited by 23 publications

References 32 publications

Tuning the Ground State Symmetry of Acetylenyl Radicals

Tuning the Ground State Symmetry of Acetylenyl Radicals

The electronic spectrum of the C s-C11H3 radical

Cavity enhanced plasma self-absorption spectroscopy

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