One-color (212–220 nm) resonantly-enhanced (S1–S0) multi-photon dissociation of acetylene

Diabatic Valence-Hole States in the C2 Molecule: “Putting Humpty Dumpty Together Again”

“…In our implementation of H-atom fluorescence action spectroscopy detection of predissociated S 1 levels of acetylene, we discovered that one-color, resonance-enhanced (S 1 ← S 0 ), multi-photon dissociation of acetylene leads to efficient production of the C 2 C 1 Π g state. − In our analysis of the dispersed fluorescence spectra of the photofragments, we were struck by the highly unusual C -state vibration-rotation structure . In Figure a–c, the vibrational energy spacings (Δ G v + 1/2 ), rotational constants ( B v ), and centrifugal distortion constants ( D v ) are shown, respectively, as a function of the C -state vibrational quantum number, v .…”

Multiphoton breakdown of acetylene; formation of organic building block fragments

“…While As mentioned above (subsection "C 2 H*(B´)/C 2 H + ") our data suggests that C 2 H*(B´) is formed after a two-photon excitation (via C 2 H 2 **) (channel (2a)). C 2 H*(B´) has been found to be a long lived species 31 formed to an increasing extent with excitation energy in one-photon excitation 27 in the region of concern, reaching quantum yield of about 6.7% for the excitation to no. 7 (see Fig.…”