The excitonic and zero-field splittings of the first triplet state of toluquinone single crystals

The pure electronic S ₀ → T ₁ transition of toluquinone has been studied in absorption using single crystals at 6 K and polarized light. The theory of the Zeeman effect on the crystal exciton levels is developed and compared with the experimental results. High-field measurements show that the factor group splitting is 0·32 cm^-1 and that the orbital plus state lies at higher energy. The ordering and energy separation of the magnetic substates of the factor group levels is also obtained. The latter results are confirmed by low field measurements and the following molecular zero-field splitting parameters are obtained: Y = +0·12, X = -0·02 and Z = -0·09 cm^-1.     

Symmetries in the triplet superconducting states

Depending upon the point-group symmetry of the system several phases occur within the superconducting state. The gap parameter for four different point group symmetries is calculated.     

New triplet states of SiO

Two new triplet states of SiO (³Σ^? and ³Π_r) which were recently predicted by ab initio calculations (J. M. Robbe, J. Schamps, H. Lefebvre-Brion, and G. Raseev, J. Mol. Spectrosc.74, 375 (1979)) were observed in emission. Fragmentary rotational analyses were performed for two transitions: ³Σ-b³Π_r and ³Π_r-b³Π_r. The following molecular constants (in cm^?1) were derived for the two new electronic states: ³Σ: T₀ ≤ 53 937, B = 0.619; ${}^3\text{Π}{}_{\mathrm{r}}\text{: T}{}_0\text{≤ 52 513, B(}\text{Π}{}_0\text{) = 0.634, A ? +23,}\text{Δ}\text{G(}\text{1}\text{2}\text{) = 589}$.     

Mechanism of the electron spin polarization of excited triplet states caused by the mutual annihilation of triplet states

A new mechanism of the triplet spin polarization is considered qualitatively and quantitatively. The spin polarization arises due to the spin-selective triplet-triplet annihilation and the subsequent spin dynamics in the spin-correlated pairs of triplets. With the time-dependent perturbation theory the simple rules are found which specify the polarization pattern of triplets.     

Excitation of triplet states of ScII from ground state scandium atoms

Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 56, No. 1, pp. 18–23, January, 1992.     

Cros-relaxation of localized triplet states in diamond

We have performed optically detected spin coherent transient measurements for two distinct localized triplet states in brown colored diamond. The triplet states of interest belong to the N?V center in its ground state and the V?O (or 2.818 eV) center in its photo-excited phosphorescent state, respectively. In this paper we focus on the dynamics of cross-relaxation processes which occur when small magnetic fields are applied in such a way that the defect triplet states of the probed centers are tuned in resonance with other defects in the lattice of different spin temperature. The coherent transients reveal the dynamics of cross-relaxation and pure dephasing processes. A quantitative analysis shows that the observed cross-relaxation arises from magnetic dipolar interactions between the probed defects and randomly distributed other defects in the lattice.     

Radiative triplet luminescence and metastable states in a-P

Previous ODMR studies showed a PL emission near 1eV which was associated with a triplet excited state. We discuss further the possible models for the ODMR signals, and show by measurement of the ODMR waveform and of the PL decay, that the experimental results are consistent with an assignment of this band to a spin-forbidden triplet exciton emission, with a lifetime ～ 4 msec. We note, however, that with chopped excitation, luminescence transients are observed which are characteristic of long-lived (τ ～ 1s) optically-created non-radiative centres.     

Confined helium: Excited singlet and triplet states

Energies for the first four singlet and triplet S states of a helium atom confined at the center of an impenetrable sphere are reported. All calculations used explicitly correlated Hylleraas basis sets. The first triplet state is shown to lie below the first excited singlet state only when the confinement radius is greater than 0.988_a0$0.988a_0$. A simple configuration interaction calculation was performed in parallel with Hylleraas calculation. The one-electron atomic orbitals of the configuration treatment provide insight into the physical concepts behind the numerical results of the Hylleraas treatment. This was particularly helpful in understanding the level crossing and avoided crossings observed with changing confinement radius.     

The lowest singlet and triplet excited states of pyrazine

The phosphoresence, fluorescence and absorption spectra of pyrazine-h₄ and -d₄ have been obtained at 4°K in a benzene matrix. For comparison, those of the isotopically mixed crystal pyrazine-h₄ in d₄ were also taken. All these spectra show extremely sharp and well-resolved lines and reveal detailed vibronic structure.The coincidence of origins of absorption and emission shows that the lowest singlet state is an allowed transition, properly designated as ${}^1\text{B}{}_{\mathrm{3u}}\text{←}{}^1\text{A}{}_{\mathrm{1g}}$. The forbidden component ¹B_2g, predicted by both “exciton” and MO theories to be below the allowed component, must lie higher. Its exact location still remains uncertain.The phosphorescence spectrum, when compared with the singlet-triplet excitation spectrum, indicates that the lowest triplet state is also symmetry allowed, showing a strong 0-0 band and the coincidence of origins of absorption and emission. In accordance with previous work, the triplet state is designated as ³B_3u.The vibronic structure of the phosphorescence spectrum is very complicated. The first work on the analysis of this spectrum concluded that a simple progression of ν_6a exists. Under the high resolution attainable in the present experiments, the supposed ν_6a progression proves to have a composite structure, starting from the second member of the progression. Not only is the ν_9a hydrogen-bending mode present as shown by the appearance of the CD bending mode in the d₄ spectrum, but a band assigned as 2ν_6b was also identified. The latter's anomalous intensity in the phosphorescence spectrum is interpreted as due to the Fermi resonance with 2ν_6a and ν_9a bands. To help resolve the present controversy over the origin of the phosphoresence spectrum observed in crystalline pyrazine, detailed vibrational analyses of the emission spectra were made. The fluorescence spectrum has essentially the same vibronic structure as the phosphorescence spectrum.     

Role of triplet states in geminal-based perturbation theory

We show that to obtain accurate potential curves by perturbing geminal-type wave functions, it is insufficient to restrict the geminals to their singlet-coupled states. Including triplet excited geminals to form four-electron singlets via the Serber coupling is essential to describe processes involving the simultaneous dissociation of two non-isolated single bonds.     

Bound ro-vibronic states of triplet H3(+)

On the basis of a new, highly accurate potential energy hypersurface for the lowest triplet state of H+3, (3)Sigma(+)(u), the bound ro-vibronic states are calculated for J相似文献   

Doubly excited triplet states of highly stripped ions

Transition energies, Coulomb repulsions and effective quantum numbers have been calculated for the doubly excited Nsnp: ³P⁰ (for N = 2, n = N,?, 5n = N,\ldots, 5); Nsnd: ³D^e (for N = 2, n=N+1, ?, 5n=N+1, \ldots, 5) and Npnd: ³F⁰ (for N = 2, n=N+1, ?, 5n=N+1, \ldots, 5) states for the highly stripped ions Na⁹⁺{\rm Na^{9+}}, Mg¹⁰⁺\rm Mg^{10+}, Al¹¹⁺\rm Al^{11+}, Si¹²⁺\rm Si^{12+}, P¹³⁺\rm P^{13+} and S¹⁴⁺\rm S^{14+}. Time-dependent perturbation theory has been applied to calculate such transitions properties. A time-dependent harmonic perturbation causes simultaneous excitation of both the electrons with a change of spin state. The doubly excited energy levels and the analytic representation of their wave functions are obtained by identifying the poles of an appropriately constructed linearized variational functional with respect to driving frequency. Most of the results are new. The transition energies and effective quantum numbers of 2s2p: ³P⁰ states of all the ions agree well with the only available experimental data.