A ²Σ⁺ ← X ²Π Electronic Absorption Spectrum of CCO^- in a Neon Matrix

Abstract

An electronic absorption spectrum of CCO -isolated in a neon matrix has been observed. The matrix was prepared by co-deposition of the mass-selected anions with excess neon at 6 K. The observed absorption spectrum is assigned to the A 2 Σ + r X 2 Π electronic transition of linear CCO -on the basis of mass-selection, photobleaching behavior, comparison with ab initio calculations, and the discernible vibrational structure. The origin band is located at 817.4(2) nm and the fundamental frequencies in the A 2 Σ + state are ν 1 (σ + ) ) 2082(3), ν 2 (π) ) 656(3), and ν 3 (σ + ) ) 1185(3) cm -1 . The ν 1 fundamental in the electronic ground state has been observed at 1876.7(1.0) in the infrared spectrum.

Electronic Absorption Spectra of C4O- and C4S- in Neon Matrixes

“…The same effect was observed in the matrix absorption spectrum of C 2 O -. 35 Considering the approximations inherent in the comparison, the calculated harmonic frequencies (Table 4) are in a satisfactory agreement with the experimental observations. The two most intense progressions present in the spectra of C 4 Oand C 4 S -(670 and 500 cm -1 , respectively) are assigned to the ν 4 stretching mode.…”

CCSD(T) Determination of the Vibrational Structure in the Ã2Σ+ ← X̃2Π Spectrum of CCO-

“…Our calculated electron affinity (2.23 eV), that agrees well with the CASPT2 result (2.22 eV) published by Zengin et al, is only 0.06 eV lower than the measured value. As for the adiabatic transition à 2 Σ + ← X̃ 2 Π, our CCSD(T) calculation gives a T 0 value (1.572 eV) consistent with the observed band origin at 1.517 eV …”

“…In contrast to the well-characterized C 2 O species, information on the negative ion CCO - remain a long time rather scarce. Initially detected in flames by mass-spectrometry, CCO - was then studied by photoelectron spectroscopy − and its à 2 Σ + ← X̃ 2 Π electronic absorption spectrum has been observed very recently in a neon matrix. Concurrently to these spectroscopic studies several works using various techniques of molecular electronic structure theory have been published lately. ,, It is well-established that the ground X̃ 2 Π and the first à 2 Σ + states are linear 3 and that the ground state is unperturbed by vibronic coupling with à 2 Σ + , situated 1.517 eV 5 above.…”

Electronic absorption spectra of C7O and C7O+ in 6 K neon matrices

“…Only the electronic transition of C 2 O in the gas phase [18], and of the two C 2 O − and C 4 O − anions in 6 K neon matrices, have been reported [19,20]. There are a few theoretical papers on the excitation energies of C 2 O, C 2 O − , C 4 O − and C 2 O + [20][21][22][23].…”