The ultraviolet absorption spectra of the oxalyl halides

Vibronic spectra, ab initio calculations, and structures of conformationally non-rigid molecules of oxalyl halides in the ground and lowest excited electronic states. Part V: Oxalyl chloridefluoride (COCl–COF)

“…These systems were assigned to thẽ A 1 A 00 X 1 A 0 andã 3 A 00 X 1 A 0 electronic transitions of the trans conformer in agreement with assignments for analogous systems of related oxalyl halide molecules [40]. As an example, a part of theà 1 A 00 X 1 A 0 spectrum of oxalyl chloridefluoride is given in Fig.…”

Vibronic spectra, ab initio calculations, and structures of conformationally non-rigid molecules of oxalyl halides in the ground and lowest excited electronic states. Part I: Reanalysis of the 3680Å and 4100Å absorption systems of oxalyl chloride

“…However, no data on the structure of the second conformers of oxalyl halides in excited electronic states are available. Earlier, only transitions of the trans-conformers were observed in the vibronic absorption spectra of oxalyl halides [14,16,[18][19][20], although according to vibrational spectroscopy and electron diffraction studies, the values of conformer energy (enthalpy) differences of oxalyl halides in the ground electronic state in the gas phase were relatively small, and the content of the second conformers was rather high [2,[4][5][6][9][10][11]22].…”

“…It was also found that upon electronic excitation to the lowest singlet and triplet electronic states, the trans-conformers of glyoxal [12,13] and oxalyl halides [14][15][16][17][18][19][20], as well as the cis-conformer of glyoxal (upon singlet-singlet excitation) [21], keep a planar structure. However, no data on the structure of the second conformers of oxalyl halides in excited electronic states are available.…”

Vibronic spectra, ab initio calculations, and structures of conformationally non-rigid molecules of oxalyl halides in the ground and lowest excited electronic states. Part III: Theoretical investigation of oxalyl fluoride

“…These studies have focused mainly on probing the dynamics of (COF) 2 upon excitation to various vibronic and rovibronic levels [3][4][5]. There have been several attempts to characterize the vibrational structure of the S 1 S 0 singlet-singlet and T 1 S 0 singlet-triplet electronic transitions of (COF) 2 [6][7][8]. However, due to the complexity of the bands' rotational contours and the absence of features from activity of the other conformer (the cis or gauche conformer), a problem common for all oxalyl halides [1], the vibrational structure of (COF) 2 has been difficult to ascertain [8].…”

“…In previous work, the vibrational [9] and vibronic [6] spectra were interpreted using only the trans (dOCCO = 180°, C 2h point symmetry) conformer. Because no transitions of the second cis conformer were observed, King et al [6,9] concluded that (COF) 2 has a strictly trans configuration.…”