Rotational Structure in the (2,0) Band of the C2 Δ3/2–X2 Π1/2 Subsystem of SbO

The rotational structure in (2,0) band of C2Δ3/2–X2Π1/2 subsystem of SbO molecule has been photographed in the third order of a 35 ft concave grating spectrograph, and the rotational constants of the two combining states have been determined. It is found that the new rotational constants for the ground state are in agreement with those reported by Rai et al., but the constants for the excited state differ appreciably from those reported earlier by Rao and Rao. A small λ-type doubling (≈4.0 × 10−6 cm−1) is observed in the excited state. The isotopic lines due to 123SbO have also been observed.

Rotational analysis of the electronic emission spectrum of the H 2 S + ion radical

The emission spectra of H 2 S + and D 2 S + occurring in the region 400 to 500 nm have been analysed in detail. In the lower 2 B 1 state both molecules are near oblate asymmetric tops, and from the rotational constants an SH(SD) bond length of 0.135 8 nm and an HSH(DSD) angle of 92.9° are obtained. In the 2 A 1 upper state of both molecules the equilibrium angle is about 127° and the SH(SD) bond length is 0.136 9 nm. The barrier to linearity in the excited state is ca . 4400 cm -1 and transitions have been observed from levels both below and above the barrier. The two combining states are shown to be derived from an electronic II state which is split by static Renner interaction. The complicated ro-vibronic structure of the excited state is interpreted in terms of a model in which both the dynamic Renner effect and spin-orbit interaction are included. The 2 A 1 state of H 2 S + is shown to play an intermediate role between the analogous high-barrier molecules such as AsH 2 (H ca . 9000 cm -1 ), and the low barrier molecules such as NH 2 (H ca . 800 cm -1 ).

THE ELECTRONIC STATES OF LINEAR METHYLENE

The electronic energy levels of the linear methylene radical, with r(C—H) = 1.0295 Å, have been calculated by the LCAO/MO/CI procedure. The state of lowest energy has 3∑g− symmetry, and is accompanied by low-lying 1Δg and 1∑g+ states. Allowed intravalence shell transitions from the ground state (3Πu−3∑g−,−3∑u−−3∑g−) are too high in energy to account for the observed transition at 8.6 ev, indicating that the latter is of Rydberg type if it is between linear combining states.

THE EMISSION SPECTRUM OF THE CCI RADICAL

A rotational analysis of the 2780 Å emission band obtained in a microwave discharge through CCl4 vapor and photographed on a 20-ft grating spectrograph shows that a 2Δi(b) → 2Πr(a) transition of the CCl radical is responsible, not 2Σ → 2Π(a) as reported by previous workers. Molecular constants are given for the combining states, as well as a vibrational analysis that identifies the 2780 Å band as the (0–0) band.