Vibronic-spin-orbit interactions in heterocyclic analogues of fluorene with the N and O heteroatoms

The transition dipole moments P _0n ^s for the transitions from the electronic triplet state ³ B ²(ππ*) to vibrational sublevels of the vibrational out-of-plane modes n of the carbazole and dibenzofuran molecules are calculated. The values of the radiative deactivation rate constant k _rad ^s of the triplet sublevels T ^s are determined along with the components k _SO ^s and k _VSO ^s of this constant, which depend on the intramolecular spin-orbit (SO) and vibronic-spin-orbit (VSO) interaction. It is ascertained that k _rad ^z > k _rad ^y . For different structural units of the molecules (the heteroatom and the carbon atoms of the dibenzene fragment), the effect of the SO coupling on the constant k _VSO～Σ_{s, n} (P _0n ^s )² is studied. A competition between the effects on k _VSO from the SO coupling in the carbon atoms and in the light N and O heteroatoms is revealed. This competition accounts for the weak influence of the heteroatom on this component of the rate constant k _rad in these molecules. It is ascertained that the intensity distribution among the vibronic lines in the phosphorescence spectra of carbazole and dibenzofuran I _0n ～Σs (P _0n ^s )² is different due to the substantially different influence of the N and O heteroatoms on the deactivation of the triplet sublevel T ^y .     

The effect of the nonplanarity of heterocyclic analogues of fluorene with the phosphorus atom on spin-orbit interactions

The transition dipole moments P ₀₀ ^S for the transitions from the sublevels s=z,y, and x of the triplet electronic states ³ A″, which are caused by intramolecular spin-orbit (SO) interactions, are calculated. The calculation is carried out for molecules of heterocyclic analogues of fluorene containing phosphorus and nitrogen (namely, the groups P-H, P-C₆H₅, and N-H). The influence that the planar and nonplanar models of the molecules, as well as the substituents ?C₆H₅ and ?H at the heteroatom (HA), exert on the values of (P ₀₀ ^S )² and on the directions of the corresponding vectors is considered. The values of the component \(k_{SO^ \sim } \sum _s (P_{00}^s )^2 \) of the radiative deactivation rate constant of the T ₁ state are calculated. It is ascertained that, in the series of molecules with HA = N, O, P, and S, both the calculated values of k _SO and those experimentally determined from an analysis of the intensity distribution in fine-structure phosphorescence spectra vary little, whereas the constant of the SO coupling in the heteroatom ?_HA increases substantially along this series. The reason for the weak influence of ?_HA on values of k _SO—common for both planar and nonplanar molecules—is found.     

Spin-orbit interactions in semiconductor superlattice

The purpose of this paper is to theoretically investigate the spin-orbit interactions of common semiconductor superlattices. Spin splitting and spin-orbit interaction coefficients are calculated based on interactions between the interface-related-Rashba effect and Dresselhaus effect. Semiconductor superlattice shows a series of specific characteristics in spin splitting as follows. The spin splitting of the superlattice structure is greater than that of a single quantum well, contributing to significant spin polarization, spin filtering, and convenient manipulation of spintronic devices. The spin splitting of some superlattice structures does not change with variation of the size of some constituent quantum wells, reducing the requirements for accuracy in the size of quantum wells. The total spin splitting of lower sub-levels of some superlattice can be designed to be zero, realizing a persistent spin helix effect and long spin relaxation time, however, the total spin splitting of higher sub-levels is still appreciable, contributing to desirable spin polarization. These results demonstrate that one superlattice structure can realize two functions, acting as a spin field effect transistor and a spin filter.     

The effect of the heteroatom on the radiative deactivation of the lowest triplet state in heterocyclic analogues of fluorene

The vibronic transition strengths F _VSO ^s for the transitions from the spin sublevels s of the triplet state T₁ to the energy levels of the nontotally symmetric vibrations of dibenzothiophene (DB(S)) are calculated. For a series of heterocyclic analogues of fluorene (DB(S) and previously studied carbazole, dibenzofuran, and phenyldibenzophosphole), the regular features of the effect of the valence state of the heteroatom and of the spin-orbit interactions in individual atomic groups of the molecule are revealed. The factors affecting changes in the radiative deactivation rate constant of the T₁ state of the molecules studied are established. The intensity distribution of the vibronic lines in the Herzberg-Teller component of the fine structure phosphorescence spectrum of phenyldibenzophosphole is calculated taking into account different populations of the triplet sublevels.     

Spin-orbit interactions from self consistent field wavefunctions

Effects of the spin-orbit Hamiltonian H_LS , including both the spin-same orbit and spin-other orbit terms, are studied at the self consistent field (SCF) level of theory. Separate calculations are carried out for each state considered, and biorthogonal orbitals are constructed for the evaluation of matrix elements. Doublet-doublet and singlet-triplet interactions are discussed. The evaluation of the Gaussian basis function integrals is described in a Cartesian component representation, these integrals being directly related to one and two electron second derivative integrals. This new SCF spin-orbit code is used to (i) determine the spatial dependence of the spin-orbit parameters for the Renner-Teller ²B₁, ²A₁ states of H₂O⁺, (ii) determine the spin-orbit splitting of the ²Π states of OH as a function of bond-length and (iii) calculate the radiative lifetime of the a ³Σ⁺ state of NO⁺. In each case these calculations are compared with more sophisticated configuration interaction studies, but it is found that the evaluation of these effects near equilibrium geometries at the SCF level is sufficiently accurate, provided that a large basis set is used.     

Non-resonant multophoton ionization of cyclopentane and its heterocyclic analogues

We report non-resonant multiphoton ionization time-of-flight mass spectra for cyclopentane, tetrahydrofuran, tetrahydrothiophene and pyrrolidine for 355 nm excitation over a wide range of laser intensities. Unlike the corresponding three-membered ring system, there is little dependence of the fragmentation pathways upon the laser intensity. The results also indicate that the mechanisms for the molecules studied cannot be generalized and are not necessarily related to those of the three-membered rings.     

Integral characteristics of vibronic-spin-orbit interactions in a phosphorus-containing analogue of the fluorene molecule

The strengths (P ₀₀ ^s )² and F _VSO ² of the transitions from the triplet sublevels s = z, y, and x of the electronic state ³A″ of the phenyldibenzophosphole (DB(P-Ph)) molecule are calculated taking into account the intramolecular spin-orbit (SO) and joint vibronic-spin-orbit (VSO) interactions. The contributions to the vibronic transition strengths from the SO interactions in different structural elements of the molecule (the C atoms of the dibenzene framework, the P atom, and the Ph substituent) are determined. The effect of the nonplanar nuclear configuration of the DB(P-Ph) molecule on the values of F _VSO ^s is investigated. The radiative deactivation rate constants of the k _rad ^s triplet sublevels T ^s are estimated. It is found that the vibrations of the A′(B₁) symmetry in the fine-structure phosphorescence spectrum of DB(P-Ph) occur due to both the SO coupling exclusively in the P atom and the T ^x → S₀ transition (the x axis is perpendicular to the planar dibenzene framework of the molecule) with a high (preferential) population of this triplet sublevel.     

Photoelectron spectra of 1,2-indandione, 1,3-indandione and heterocyclic analogues

The photoelectron (He(I)) spectra of 1,2-indandione and heteroanalogues (coumarandione, thionaphthenequinone, and isatin), 1,3-indandione and heteroana     

Spin-orbit potential in sulfur isotopes

The effects of the spin-orbit interaction in exotic nuclei are investigated by studying the binding energies and deformations of Si, S and Ar isotopes. The calculations were obtained by Skyrme-Hartree-Fock model with various spin-orbit potentials. The results reveal that spin-orbit potential is important in neutron rich nuclei.     

Spin-orbit potential in heavy-ion collisions

The spin-orbit potentials between heavy-ion projectiles and ¹²C target are calculated by the folding method. The projectile mass number dependence of the spin-orbit potential is presented. The contributions of the spin-orbit potential to the elastic and inelastic scatterings of the ⁶Li and ¹⁴N projectiles from the ¹²C target are calculated. The theoretical elastic polarization of the ⁶Li scattered from ¹²C is found to be appreciable.     

Spin-orbit forces in knockout reactions

The spin-orbit final-state interaction for the one-nucleon knockout reaction is studied in perpendicular kinematics using an eikonal formalism to investigate experimentally observed cross- section asymmetries. Our results elucidate previous numerical calculations indicating sensitivity of these asymmetries (as a function of the nuclear recoil momentum) to the imaginary part of the spin-orbit potential.     

Spin-orbit coupling in Σ-hypernuclei

Single-particle energies of Σ-hyperons in _Σ¹⁶O are calculated within a relativistic mean-field theory. This model predicts a small spin-orbit splitting for Σ-hyperons in _Σ¹⁶O compared to ordinary nucleons in nuclei. Half of the small spin-orbit splitting is due to the anomalous magnetic moment of the Σ-hyperon. K and K¹ exchange terms are negligible. This is to be seen in contrast to a previous quark-model prediction of a strong spin-orbit splitting for hyperons.     

光在Metasurface中的自旋-轨道相互作用

探讨了光在Metasurface中的自旋-轨道相互作用, 理论分析了Metasurface 对圆偏振和线偏振光的转换. 结果表明: 光与具有空间非均匀性和各向异性性的Metasurface的相互作用导致了自旋-轨道角动量的耦合. 采用Metasurface与螺旋相位片组合在一起进行了验证实验, 所得实验结果与理论分析完全一致. 这些结论有助于我们更加深入理解Metasurface 对光的操控.     

Spin-orbit interaction in strongly deformed nuclides

Mass yields observed in asymmetric fission are used to constrain the parameterization of the spin-orbit term of the neutron single particle potential at large deformations.     

Spin-orbit interaction in coupled quantum wells

We theoretically investigate the spin-orbit interaction in GaAs/AlxGa1 x As coupled quantum wells. We consider the contribution of the interface-related Rashba term as well as the linear and cubic Dresselhaus terms to the spin splitting. For the coupled quantum wells which bear an inherent structure inversion asymmetry, the same probability density distribution of electrons in the two step quantum wells results in a large spin splitting from the interface term. If the widths of the two step quantum wells are different, the electron probability density in the wider step quantum well is considerably higher than that in the narrower one, resulting in the decrease of the spin splitting from the interface term. The results also show that the spin splitting of the coupled quantum well is not significantly larger than that of a step quantum well.     

Spin-orbit coupling in the chlorobenzene molecule

The possible ways of drawing of the intensity of the S₀ T* transition in the chlorobenzene molecule are investigated. The effective spin-orbit coupling of either S* or S* states with the T* state leads to the out-of-plane polarized component of phosphorescence in the chlorobenzene. The in-plane polarized component cannot be explained by the mechanism under consideration — by drawing of intensity of the S₀ S₀* transitions through spin-orbit coupling of first order.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 134–138, August, 1974.