Slow photoelectron velocity-map imaging spectroscopy of C2N−, C4N−, and C6N−

Abstract

High resolution photoelectron spectra of C(2)N(-), C(4)N(-), and C(6)N(-) anions are reported, obtained using slow electron velocity-map imaging. The spectra show well resolved transitions to the X (2)Pi neutral ground state of all three species and to the a (4)Sigma(-) excited state of C(2)N and C(4)N. This study yields the adiabatic electron affinity of C(2)N, C(4)N, and C(6)N, the spin-orbit splitting in the X (2)Pi state of each radical, and the term energy of the a (4)Sigma(-) state in C(2)N and C(4)N. Relatively little vibrational activity is observed, indicating small geometry changes upon photodetachment. This result, plus the observation of transitions to neutral quartet states, indicates that the C(2n)N(-) (n=1-3) anions all have linear (3)Sigma(-) ground states.

Accurate ab initio ro-vibronic spectroscopy of the $\tilde X^2 \Pi$X̃2Π CCN radical using explicitly correlated methods

“…As this radical is isoelectronic with CCN, a similar excited state may also be important to the spectroscopy of the present investigation, especially in terms of its interaction via spin-orbit coupling. The MRCI calculations (including zero point correction) of Pd and Chandra 3 predicted the a 4 Σ -state to be 8322 cm -1 higher than the ground state for CCN, which is in good agreement with the recent observation of this state by slow photoelectron velocity-map imaging spectroscopy by Neumark and co-workers, 22 T 0 = 8413 ± 8 cm -1 .…”

Infrared Photodissociation Spectroscopy of C2n+1N− Anions with n = 1 – 5

“…The latter results are supported by the SEVI experiments of Garand et al and Yen et al [21,22]. Botschwina et al performed a detailed theoretical analysis of the C 2n+1 N − ( = 1-6) anions using coupled cluster theory combined with large basis sets and predicted, among other spectroscopic constants, their equilibrium structures as well as harmonic ( = 1-6) and anharmonic ( = 1-3) vibrational frequencies [18,24].…”

“…In their matrix studies, which mainly focused on the electronic transitions of C 2n+1 N − ( = 2-6) anions, Grutter et al [19] also reported the IR absorption spectra of the smaller anions and found evidence for a few IR transitions for C 5 N − , C 7 N − and C 9 N − . Garand et al and Yen et al [21,22] investigated the anion photoelectron spectra of the C n N − ( = 2-6) clusters using slow electron velocity-map imaging (SEVI) and determined adiabatic electron affinities for C 3 N and C 5 N, as well as vibrational frequencies for the fundamentals of the degenerate cis (538 cm −1 ) and trans (208 cm states for the anions with odd and even number of carbon atoms, respectively [23].…”

Ground and low-lying excited states of propadienylidene (H2C=C=C:) obtained by negative ion photoelectron spectroscopy

“…The gas mixture, at a stagnation pressure of 300 psi, was expanded into the source vacuum chamber through an EvenLavie pulsed valve 49 equipped with a grid discharge described in detail in Ref. 50. Anions formed in the gas expansion were perpendicularly extracted into a Wiley-McLaren TOF-MS (Ref.…”