The 5340 Å band system of thiocarbonyl chloride

The high resolution photoelectron spectra of phosgene and thiophosgene have been obtained and, in each case, all ionization potentials up to 21.2 eV determined. The spectra are interpreted in terms of the molecular orbital structures and it is concluded that there is a strong interaction between the chlorine p, "lone pair" electrons and those in the C=O or C=S 71 bond. The measured ionization potentials are compared with those calculated by the CNDO/2 method and with those obtained for similar molecules.On a obtenu le spectre phototlectronique a haute rtsolution du phosgtne et du thiophosgtne et dans chaque cas, on a dktermint tous les potentiels d'ionisation jusqu'a 21.2 eV. On a interprttt les spectres en termes de structures d'orbitales moltculaires et on a conclu qu'il existe une forte interaction entre la paire d'klectrons libres du chlorep, et ceux de la liaison 71 du C=O ou du C=S. On a compart les potentiels d'ionisation mesures a ceux calcults par la mtthode CNDO/2 et ceux obtenus pour des molkcules semblables.

Section: Resultsmentioning

confidence: 99%

Photoelectron Spectra of Phosgene and Thiophosgene

Chadwick¹

1972

“…The A(IA2) state is very wellcharacterized spectroscopically (14,15). Since this state is used only as an intermediate in the present study a detailed review of our current understanding of it will be omitted.…”

Section: Introductionmentioning

confidence: 99%

“…The reader can refer to recent reviews. It suffices to know here that the extensive vibronic analyses of Brand et al (15) together with the few minor reassignments of Clouthier and Moule (14) have been used to select the energies and symmetries of the intermediate levels in our OODR scheme. We consider the latter two works to be essentially accurate.…”

Section: Introductionmentioning

confidence: 99%

Optical–optical double resonance study of the and &([a-z]+);(³A₂) states of thiophosgene

Simard¹,

Mackenzie²,

Hackett³

et al. 1994

The &([a-z]+);(3A2) and [Formula: see text] states of jet-cooled thiophosgene (Cl2CS) have been studied by optical–optical double resonance (OODR) spectroscopy. Two OODR schemes have been used to probe the [Formula: see text] state. One scheme uses selected vibronic levels of the &([a-z]+);(1A2) state as the intermediate state, while the other uses the vibrationless and 2131 levels of the &([a-z]+);(3A2) state. All of the vibronic levels in the 33 980−35 600 cm−1 region can be rationalized with the following origin band and fundamentals: 0° = 34 277 cm−1, v1 = 505 cm−1, v2 = 470 cm−1, v3 = 213 cm−1, v6 = 249 cm−1, 42 = 341 cm−1, 44 = 627 cm−1. The discrepancies among the various studies of the [Formula: see text] state will be discussed and reconciled. It is conjectured that the [Formula: see text] state potential along the C—S coordinate exhibits an asymmetric double-minimum potential resulting from the interaction of the 1A1 states arising from the [Formula: see text] configurations. The minimum corresponding to the [Formula: see text] configuration lies higher in energy and the principal decay mechanism for molecules pumped to its first few vibronic levels is fluorescence. On the other hand, molecules pumped to the minimum corresponding to the nominal [Formula: see text] configuration decay nonradiatively. The barrier height to inversion and the out-of-plane bending angle along the out-of-plane bending coordinate, v4, have been determined to be 945 cm−1 and 25°, respectively, by fitting quartic-quadratic and quadratic-Gaussian double-minimum potentials to the observed energy levels. The &([a-z]+);(3A2) state has been studied by a novel OODR scheme which uses the fluorescent vibrationless level of the [Formula: see text] state to monitor [Formula: see text]transitions. A vibronic analysis has been carried out and the following origin band and fundamentals derived for the &([a-z]+);(3A2) state: 0° = 17 499 cm−1, v1 = 923 cm−1, v2 = 474 cm−1, v3 = 247 cm−1, 42 = 297 cm−1, 44 = 560 cm−1, 46 = 741 cm−1. With the exception of a few corrections and additions, the results confirm the findings of previous studies, notably regarding the bent geometry and barrier height to inversion. An overall comparison of the data suggests that the wavenumber of v6 in theÃ(1A2) state is 279 cm−1 instead of 189 cm−1.

“…The room temperature crystal structures of several pyridiiliuin salts have been determined by X-ray methods (1)(2)(3). It is typical of these structures that large ailisotropic temperature factors are observed and, in some cases, a disordering of the ring positions or difici~lties in distiilguishing directly between carbon and nitrogen atoms have been reported.…”

Section: Introductionmentioning

confidence: 99%

The ³A₂ state of thiocarbonyl difluoride

Moule¹

1970

Self Cite

The 4500 b. band system of thiocarbonyl difli~oride F,CS has been photographed ~~n d c s conditions of moderately high resolution and has been assigned to the activity of the v , , v,, v,, and v, modes arising from the 3A, + lA, electronic transition. T h e out-of-plane wagging levels were f o~~n d t o be strongly anharmonic, the observed inversion doubling indicating that the maximum in the potential f~~n c t i o n was greater than 3100 cm-I.