Ab initio predictions of the zero field splittings and the singlet–triplet transition strengths for the n → π* transition of selenoformaldehyde

Abstract

. Can. J. Chem. 71, 1706 (1993). The energy levels of the lower valence and Rydberg states of selenoformaldehyde, CH2Se, have been calculated by the SCF/CI method. Wavefunctions for the ROHF (restricted open shell Hartree-Fock) states were obtained with the Binnings-Curtis double-l; basis set, augmented with Rydberg and polarization functions. Configuration interaction was applied to the parent configurations, PCMO (parent configuration molecular orbital). Oscillator strengths were evaluated for the allowed electric dipole transitions by the RPA (random phase approximation), and SOPPA (second-order polarization propagator approximation) methods. The spin-orbit contribution to the zero field splitting of the first triplet state, 3~2(n,m*) as well as the oscillator strengths to the three spin components were calculated by perturbation theory. These calculations predict that the S,, S,, and S, components are shifted by -96.091, -96.707, and +29.167 cm-', respectively, from their unperturbed position. The oscillator strengths for the three componentsf,, f,, andf; of the 'A2(n,m*) t 'A,(g.s.) transition were calculated to be 3. On a applique l'interaction de configuration aux configurations fondamentales, PCMO (orbitale molCculaire de la configuration fondamentale). Faisant appel aux mCthodes de RPA (approximation alCatoire de la phase) et SOPPA (approximation du deuxieme ordre de la polarisation du propagateur), on a CvaluC les forces de l'oscillateur pour les transitions tlectriques dipolaires permises. Utilisant la thCorie de perturbation, on a calculC la contribution spin-orbite au couplage Introduction The CH2X molecules, where X = 0 , S , and Se, may be

A Study of the Higher Electronic Transitions of Selenoformaldehyde, CH2Se

“…Table 1 gives a summary of the calculated and observed electronic transition of selenoformaldehyde in the near IR and far UV. The agreement between the most recent calculated positions (12) and the observed values for the UV transitions is satisfactory with the same relative error as for the near IR transitions. Table 2 and Fig.…”

“…Recent ab initio calculations (12,13) place both the 3 * transition and the n Ϫ 5s Rydberg transition in this region. Table 1 gives a summary of the calculated and observed electronic transition of selenoformaldehyde in the near IR and far UV.…”

Contribution to the Analysis of the3A2←X1A1“Wulf” Transition of Ozone by High-Resolution Fourier Transform Spectrometry

“…The modest increase from the oxygen to sulphur compound may be attributed mainly to the increase in the atomic spin-orbit coupling parameter, , of oxygen over sulphur. The dramatic increase from sulphur to selenium is attributed not to the increase in , but rather to the location of a nearby 3 A 1 state that displaces the Խx͘ and Խy͘ spin states to lower energy (28). With two other triplet states expected to lie near the 3 A 2 state, it is likely that the diminishing effect of the lower value of of oxygen over S in SO 2 is compensated by the level perturbations of the other nearby states.…”

Evaluation of low-scaling methods for calculation of phosphorescence parameters

“…The S 0 -T 1 spectra in the H 2 CX molecules have been exhaustively studied with high resolution [2][3][4][5][6][7][8] in spite of the fact that formaldehyde is the only chemically stable species in this series. The S 0 -T 1 spectra in the H 2 CX molecules have been exhaustively studied with high resolution [2][3][4][5][6][7][8] in spite of the fact that formaldehyde is the only chemically stable species in this series.…”

“…The S 0 -T 1 spectra in the H 2 CX molecules have been exhaustively studied with high resolution [2][3][4][5][6][7][8] in spite of the fact that formaldehyde is the only chemically stable species in this series. 9 Other aldehydes X = ͕S,Se͖ are extensively studied as transient molecules by pyrolysis, 3 photolysis, 6,7 or chemiluminescence spectra 8 in gas phase. 8 At the same time telluroaldehydes are known as bridging ligands in some metal complexes.…”