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; ${}^3\text{Π}{}_{\mathrm{r}}\text{: T}{}_0\text{≤ 52 513, B(}\text{Π}{}_0\text{) = 0.634, A ? +23,}\text{Δ}\text{G(}\text{1}\text{2}\text{) = 589}$.     

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.     

Spin polarization in triplet states in solution

A method is described for measuring the absolute value of the spin polarization in a triplet state in solution through CIDEP observations of the radicals formed on its reaction, and through it the anisotropy of the rates of the spin-selective intersystem crossing process. A long-accepted equation concerned with triplet mechanism spin polarization is shown to be inadequate to reproduce observed behaviour, and evidence produced to suggest that the observed polarization is affected by radical relaxation. The method also allows determination of the absolute polarization in the radicals. A novel analysis of the relative contributions of TM and RPM processes to observed spectra provides further evidence for the conclusions.     

The electronic states in diamond

An account of a method of performing a priori tight-binding calculations on a crystal lattice of the diamond type is given. The method is a generalization of that of Cohan et al. [8]. Certain possible extensions of the method are discussed. New results for the electronic energy bands in diamond are presented in which the variation of the bands with the hybridization parameter of the initial bonding orbitals and the orbital exponent of the basic atomic orbitals is investigated.     

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.     

Hydrocarbon ions with triplet ground states

The N.M.R. spectra of meta dichloro and meta dibromo benzenes are analysed in the nematic phase of 4-methoxy benzylidene-4-amino-α-methyl cinnamic acid-n-propyl ester at room temperature.

The direct couplings are found to be of negative sign. The molecules orient preferentially with the aromatic plane along the direction of the magnetic field and the C ₂-symmetry axis perpendicular to it.

The relations between the various direct couplings and the inter-proton distances are reported. The ratio of the distance between the meta protons along the axis perpendicular to the C ₂ symmetry and the ortho protons is determined precisely. The other ratios could not be determined to any reasonable precision. The reasons are discussed.

The angles between the C-H bonds of the equivalent protons and the C-C bonds in both the molecules are determined on the assumption of the C-H bond lengths and the ring geometry of benzene.     

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.     

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.     

Polaron-type localized states in ferroelectric ferroelastics

The problem of a charged particle in an improper ferroelectric ferroelastic is considered. The existence of the ground and first excited states of the discrete spectrum is established and their dependence on the parameters of the problem is investigated using a direct variational method.     

Vibronic coupling to nearly localized modes in diamond

The presence of sharp low energy vibronic progressions in several luminescing bands of brown diamonds is interpreted as due to a nearly localized vibrational mode, showing a weak coupling to resonant lattice phonons. The effect of this mode on the vibronic coupling is discussed and compared with experimental data.     

NMR of localized magnetic states in graphene

The NMR relaxation rate is studied on the magnetic states of an impurity in bilayer graphene within a tight-binding scenario. The dependencies of the relaxation rate on temperature, interlayer interaction and also the chemical potential have been considered. Although for low temperatures we observe the usual Korringa relation, a characteristic of the conventional fermions, the rate increases with the increase in temperature and tends to saturate for high temperatures. For small interlayer interactions (t_⊥) the system can be either magnetic or non-magnetic. However for higher t_⊥ we observe the existence of only a pure magnetic state. In graphene this transition is also observed with two cusps related to the magnetic to non-magnetic transition, which modifies to a single hump for higher t_⊥, where the system is purely magnetic for any value of chemical potential.     

Temperature-dependent localized excitations of doped carriers in superconducting diamond

Laser-excited photoemission spectroscopy is used to show that the doped carriers in metallic or superconducting diamond couple strongly to the lattice via high-energy (approximately 150 meV) optical phonons, with direct observations of localized Franck-Condon multiphonon sidebands appearing as Fermi-edge replicas. It exhibits a temperature-dependent spectral weight transfer from higher to lower energy sidebands and zero-phonon Fermi-edge states. The quantified coupling strength shows a systematic increase on lowering temperature, implicating its relation to the normal state transport and superconductivity.     

Determination of localized states in porous silicon

We determined the density of state distribution near the Fermi level in porous silicon from the analysis of the current–voltage (J–V) and the current–thickness (J–T) characteristics in the space-charge-limited-current (SCLC) regime. The distribution exhibits a minimum density at the Fermi level, which is similar to the U-shape-trap-distribution observed in crystalline Si–SiO₂ interface or in amorphous Si. Theoretical analysis well explains both the J–V and the J–L characteristics, which implies that the current flow is entirely controlled by localized states situated at the quasi-Fermi level.     

Observation of localized d states in metals

By application of the perturbed γ-ray distribution method combined with heavy-ion reactions and recoil implantation techniques, we have found an experimental was of producing and investigating localized 3d and 4d states in metals. 3d and 4d ions in sp metal hosts, in particular in alkali metals, exhibit the phenomena of large orbital magnetism, extremely small spin fluctuation rates, well defined ionic ground states, mixed valence, and crystal field splittings smaller than theLS coupling. These results upset long standing assumptions about the nature of d states in metals and their magnetic instabilities due to interaction of d orbitals with conduction electrons. If magnetic, the d states of 3d and 4d ions cannot be described by one electron approaches based on Anderson type models but required an analysis based on ionic configurations. The tendencies towards reduced magnetism can be well reproduced by increasing spin fluctuations which gives new insight into antiferromagnetic d-sp exchanges and the Kondo problem for d ions in sp metals. Localized ionic d states, large orbital effects, small crystal fields, and mixed valence-these new phenomena for d ions in sp metals exhibit common basic features with stable and unstable 4f and 5f systems but reflect qualitative differences to the spin dominated magnetism of 3d ions in Cu, Ag, Au and in d metal hosts.     

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