Photoelectron spectra of the C2nH− (n=1–4) and C2nD− (n=1–3) anions

Abstract

Articles you may be interested inTemperature-dependent Raman and ultraviolet photoelectron spectroscopy studies on phase transition behavior of VO2 films with M1 and M2 phases J. Appl. Phys. 115, 153501 (2014); 10.1063/1.4870868Ammonia cluster anions and their relationship to ammoniated (solvated) electrons: The photoelectron spectra of ( NH 3 ) n=41-1100 − Anion photoelectron spectra of the carbon monohydrides, C 2n H Ϫ for nϭ1 -4 and C 2n D Ϫ for nϭ1 -3, have been measured. The spectra were recorded at a wavelength of 266 nm ͑4.657 eV͒ and yield electron affinities for each species. The spectra are vibrationally resolved, and some of the vibrational modes in the neutral C 2n H͑D͒ radicals are assigned. In addition, photoelectron angular distributions allow one to distinguish between photodetachment transitions to the 2 ⌺ ϩ and 2 ⌸ states of the neutrals. The spectra confirm previous work showing that C 2 H and C 4 H have 2 ⌺ ϩ ground states, while C 6 H and C 8 H have 2 ⌸ ground states. In addition, we observe the low-lying 2 ⌸ or 2 ⌺ ϩ excited states for all four radicals. The photoelectron angular distributions also serve as a probe of vibronic coupling between the 2 ⌺ ϩ and 2 ⌸ states. These effects are particularly prominent in the C 2 H Ϫ and C 4 H Ϫ spectra.

C6H and C6D: Electronic spectra and Renner-Teller analysis

“…Previous studies 15,16,34,38,39,41 show that the order of the first two electronic states, X Table III 32,38 have shown that conjugated bond systems become more stable with increasing the chain length of the homologues C 2n H radicals. The slightly stronger electronic SO coupling in C 6 H may arise from the higher stability of the conjugation in a longer chain.…”

“…kT (15) where N is the population density of C 6 H in separate lowlying vibronic levels, and T is the temperature (in Kelvin). 2 , should be determined by the same effective vibronic temperature, i.e., the temperatures T in Eqs.…”

“…Refs. 10 and 11), it became possible to record the electronic spectra of C 6 H, [12][13][14][15] among many other carbon chain radicals. In a combined microwave and optical study 16 the rotationally fully resolved origin band spectra of the B 2 -X 2 electronic system of C 6 H and C 6 D were analyzed, resulting in accurate spectroscopic parameters for both 2 states.…”

HIGH-ACCURACY QUARTIC FORCE FIELD CALCULATIONS FOR THE SPECTROSCOPIC CONSTANTS AND VIBRATIONAL FREQUENCIES OF 11A′l-C3H–: A POSSIBLE LINK TO LINES OBSERVED IN THE HORSEHEAD NEBULA PHOTODISSOCIATION REGION

“…As discussed by Gupta et al (2007) and , the need for radical excitation followed by RA could explain the very low [C 4 H − /C 4 H] ratio observed toward various interstellar objects (Agúndez et al 2008;Cordiner et al 2013). Even though these two states of C 4 H are "nearly degenerate" (Taylor et al 1998), some additional energy is required to populate the A 2 Π state, which, in turn, lowers the probability of electron attachment. Furthermore, C 2 H is also 2 Σ + in its ground state, but the excitation energy into the large-dipole A 2 Π state is more than double its counterpart in C 4 H (Fortenberry et al 2010), which may shed light on the even lower [C 2 H − /C 2 H] ratio proposed by Agúndez et al (2008).…”

The fractional ionization in dark molecular clouds

“…2.2 below), can be the small difference between two much larger numbers. As the electron affinities of both C 6 H and C 4 H (Taylor et al 1998) are larger than those of the PAH (Modelli & Mussoni 2007), electron transfer from PAH − to C 6 H and C 4 H is energetically possible and has been included in our reaction set with a rate coefficient of 1.7 × 10 −9 cm 3 s −1 . However, as will be seen in Sect.…”