Magnetic Rotation Spectrum and Heat of Dissociation of the Potassium Molecule

The absorption spectra and magnetic rotation spectra of the [Formula: see text],[Formula: see text],[Formula: see text], and [Formula: see text] bands of the [Formula: see text] system of formaldehyde have been studied at high resolution. The earlier analyses of the absorption bands have been refined and improved molecular constants obtained. Several singlet–singlet perturbations have been noted and possible mechanisms discussed.The magnetic activity falls into two classes. Three of the bands show limited singlet–singlet activity with characteristics similar to those found earlier for the [Formula: see text] and [Formula: see text] bands. All the bands show singlet–triplet activity which is characterized by the appearance of rR, rP, pR, and PP transitions associated with a common upper level. Tables of perturbed excited-state singlet levels are given. No appreciable shifts of the perturbed levels have been found indicating that the matrix elements are small. For the [Formula: see text] band two perturbation mechanisms are proposed and the vibrational symmetries and energies of the perturbing triplet states are determined. The energies are too high to permit unambiguous vibrational assignments.

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The magnetic rotation spectrum of singlet-triplet transitions

Journal of Molecular Spectroscopy ◽

10.1016/0022-2852(61)90271-5 ◽

1961 ◽

Vol 6 ◽

pp. 483-491 ◽

Cited By ~ 55

Author(s):

W.H. Eberhardt ◽

H. Renner

Keyword(s):

Magnetic Rotation ◽

Rotation Spectrum

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The magnetic rotation spectrum of formaldehyde: singlet–triplet perturbations in the 41 and 43 levels of the Ã1A2 state of H2CO

Canadian Journal of Physics ◽

10.1139/p79-171 ◽

1979 ◽

Vol 57 (8) ◽

pp. 1224-1232 ◽

Cited By ~ 23

Author(s):

D. A. Ramsay ◽

S. M. Till

Keyword(s):

Absorption Spectrum ◽

High Resolution ◽

Rotational Level ◽

Magnetic Rotation ◽

Matrix Elements ◽

Coriolis Interaction ◽

Near Ultraviolet ◽

The Matrix ◽

Rotation Spectrum

A survey of the magnetic rotation spectrum (MRS) of formaldehyde in the near ultraviolet is reported. The [Formula: see text] and [Formula: see text] bands of the [Formula: see text] system are also studied under high resolution. The rR and pP branches of these bands are found to be active and it is noted that the intensities appear to increase more rapidly with increasing Ka in the MRS than in the absorption spectrum. The 43 and 61 levels are in Coriolis interaction at higher Ka values, and some rR branches of the [Formula: see text] band are identified.Several strong lines in the MRS are shown to be associated with rR, rP, pR, and pP lines in the absorption spectrum and to reveal the presence of singlet–triplet perturbations. Only one perturbed rotational level is found in the [Formula: see text] band, but for the [Formula: see text] band several rotational levels are found to exhibit such perturbations, e.g. 190,19, 191,19, 171,16, 102,8, 102,9, 112,9, 173,14, 173,15, 183,15, and 183,16. These perturbations are produced by ΔJ = ΔN = ΔKa = 0 interactions with the 415161 level of the ã3A2 state and by ΔJ = ΔN = 0. ΔKa = ± 1 interactions with the 5161 level. The matrix elements are of the order of 0.01–0.10 cm−1.

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