Solvatochromism of Free-Base Corroles

Journal of Applied Spectroscopy - Solvatochromic shifts of absorption bands are determined in a series of solvents of different nature for two free-base corroles with different peripheral...     

Laser Induced Lowest Triplet State Properties of Dibenzothiophene in Solution

Laser induced triplet state lifetimes are measured in the presence of air and for oxygen, air, argon saturated, and vacuum degassed solution of dibenzothiophene in solution at room temperature by triplet decay, including the prompt and p-type delayed fluorescence. The results are discussed and compared to those of molecules with the same symmetry.     

Deactivation of the S2 and Two Lowest Triplet States of 4H-1-Benzopyran-4-thione and Its Alkyl Derivatives in Methanol Solution

Spectral and photochemical properties of three aromatic thioketones, 4H-1-benzopyran-4-thione and its two alkyl derivatives, in their second excited singlet and two lowest triplet states have been a subject of stationary and time-resolved studies. Quantum yields of emissions from the above-mentioned states as well as lifetimes of these states have been measured. The results indicate an important role of intermolecular solvent-induced processes in deactivation of the excited states of the thioketones studied. The possible mechanism of these processes involves hydrogen atom abstraction and/or formation of exciplex. For relatively high thione concentrations, the contribution of self-quenching in deactivation of the triplet states becomes significant. The effect of the alkyl chain in a thione molecule on deactivation parameters is discussed.     

4-硝基联苯酚三重态质子化和去质子化过程中瞬态物种的指认

近年利用超快光谱技术对于4-硝基联苯酚(HO-Bp-NO₂)的研究发现,其在单重态和三重态时均会发生光致质子耦合电子转移(PCET)反应. 其瞬态吸收光谱450 nm处有一个独特的尖锐吸收带,但无羟基取代的对硝基联苯(Bp-NO₂)未观察到此现象. 本文利用酸性溶液作为外加可控质子供体,通过在强酸(∽10^-1 mol/L)和弱酸(∽10^-4 mol/L)溶液中的光谱和动力学结果,指认这个新吸收带为开壳层单重态O-Bp-NO₂H. 它是HO-Bp-NO₂的互变异构体,由三重态HO-Bp-NO₂中硝基氧得质子后羟基快速去质子产生. 动力学分析表明,非质子极性溶剂中三重态HO-Bp-NO₂与基态母体间还会发生PCET或先质子后电子转移生成自由基·O-Bp-NO₂. 这一反应与O-Bp-NO₂H竞争,导致其产率较低. 这些结果阐明了三重态HO-Bp-NO₂在非质子极性溶剂中的失活机制.     

Triplet excitations at high temperatures in 1:1 TCNQ-salts

High temperature properties of triplet excitations in TCNQ-salts are theoretically studied. Formulas for the energy and concentration of triplet excitons as functions of temperature are obtained. The static magnetic susceptibility of triplet excitons is calculated. A possible appearance of short range order in the excitation density is discussed. A high-concentration modification of the molecular exciton theory is used throughout the paper.I would like to express thanks to Dr. W.Siebrand of N.R.C., Ottawa, for introducing me into problems in charge-transfer crystals. I also thank Professor M.Trlifaj for interesting discussions.     

Ab Initio Calculation of the Lowest Singlet and Triplet Excited States of the N<Subscript>2</Subscript> Molecule

Ab initio calculations of the adiabatic potential curves and matrix elements of radial nonadiabatic coupling of the N₂ molecule for the states related to dissociation limits I–V were performed. The most important spectral characteristics of the adiabatic states agreed well with the available experimental and theoretical data. The diabatic states were constructed. The diabatic quantum defects and radial matrix elements of the configuration interaction of the dissociative and Rydberg configurations whose states converge to the ground state \(X^{2}\Sigma{_g^+}\) and the first electronically excited state A²Π_u of the \(\rm{N_2^+}\) ion were calculated. The possibility of using the results for calculating the cross sections and rate constants of dissociative recombination and associative ionization within the framework of the multichannel quantum defect theory was discussed.     

Spin Triplet Superconducting State due to Broken Inversion Symmetry in Li(2)Pt(3)B

We report (11)B and (195)Pt NMR measurements in noncentrosymmetric superconductor Li(2)Pt(3)B. We find that the spin susceptibility measured by the Knight shift remains unchanged across the superconducting transition temperature T(c). With decreasing temperature (T) below T(c), the spin-lattice relaxation rate 1/T(1) decreases with no coherence peak and is in proportion to T3. These results indicate that the Cooper pair is in the spin-triplet state and that there exist line nodes in the superconducting gap function. They are in sharp contrast to those in the isostructural Li(2)Pd(3)B which is a spin-singlet, s-wave superconductor, and are ascribed to the enhanced spin-orbit coupling due to the lack of spatial inversion symmetry. Our finding points to a new paradigm where exotic superconductivity arises in the absence of electron-electron correlations.     

Logarithmic Corrections and Finite-Size Scaling in the Two-Dimensional 4-State Potts Model

We analyze the scaling and finite-size-scaling behavior of the two-dimensional 4-state Potts model. We find new multiplicative logarithmic corrections for the susceptibility, in addition to the already known ones for the specific heat. We also find additive logarithmic corrections to scaling, some of which are universal. We have checked the theoretical predictions at criticality and off criticality by means of high-precision Monte Carlo data.     

Effect of Temperature on the Rate of Triplet–Triplet Annihilation of 1,2-Benzanthracene in a Polymer Matrix

The process of triplet–triplet annihilation (TTA) of 1,2-benzanthracene (1,2-BA) incorporated into polymer films of polyvinyl butyral has been investigated in the temperature interval 80–360 K. An analysis of the kinetics of the decay of delayed annihilation fluorescence (DAF) of 1,2-BA has shown that the process of the triplet excitation energy transfer in a disperse medium of the polymer at distant times of the DAF decay can be described using the approximation of random walks of the triplet energy in the inhomogeneous medium of the polymer. At low temperatures, at the initial times of DAF decay the TTA process is described with the aid of a model of static annihilation.     

Lowest energy Cooper pairing in the presence of antiferromagnetism

Cooper pairing of electron eigenstates of an antiferromagnet involves considerable complexity in spin space and in phases of the order parameters. With a BCS interaction the pairing scheme with lowest free energy has anisotropic spin-matrix order parameter $\textcolor{red}{}\text{(}\text{k}\text{); however}\textcolor{red}{}{}^{\mathrm{+}}\text{(}\text{k}\text{)}\textcolor{red}{}\text{(}\text{k}\text{)=|△|}{}^2\textcolor{red}{}$. Magnitude of the anisotropic order parameter satisfies the simple BCS gap equation but with electron energies of the antiferromagnet eigenstates appearing instead of Bloch state energies of the nonmagnetic crystal.     

Triplet based online track finding in the PANDA-STT

We present a method for online track finding in the PANDA-STT which requires only knowledge of the time and straw position of the hits. Therefore, it does not depend on any additional information such as the drift-time or radius drift-time calibration which may not be present ab-initio.     

Triplet superconductivity in a 1D itinerant electron system with transverse spin anisotropy

In this paper we study the ground state phase diagram of a one-dimensional t-J-U model away from half-filling. In the large-bandwidth limit and for ferromagnetic exchange with easy-plane anisotropy a phase with gapless charge and massive spin excitations, characterized by the coexistence of triplet superconducting and spin density wave instabilities is realized in the ground state. With increasing ferromagnetic exchange transitions into a ferrometallic and then a spin gapped triplet superconducting phase take place.     

Unusual Corrections to Scaling in the 3-State Potts Antiferromagnet on a Square Lattice

At zero temperature, the 3-state antiferromagnetic Potts model on a square lattice maps exactly onto a point of the 6-vertex model whose long-distance behavior is equivalent to that of a free scalar boson. We point out that at nonzero temperature there are two distinct types of excitation: vortices, which are relevant with renormalization-group eigenvalue 1/2 and non-vortex unsatisfied bonds, which are strictly marginal and serve only to renormalize the stiffness coefficient of the underlying free boson. Together these excitations lead to an unusual form for the corrections to scaling: for example, the correlation length diverges as J/kT according to Ae ² (1+be ^– +···), where b is a nonuniversal constant that may nevertheless be determined independently. A similar result holds for the staggered susceptibility. These results are shown to be consistent with the anomalous behavior found in the Monte Carlo simulations of Ferreira and Sokal.     

Distribution of Triplet Separators in Bacterial Genomes

Distributions of triplet separator lengths for two bacterial complete genomes are analyzed. The theoretical distributions for the independent random sequence and the first-order Markov chain are derived and compared with the distributions of the bacterial genomes. A prominent double band structure, which does not exist in the theoretical distributions, is observed in the bacterial distributions for most triplets.     

Structure of the Triplet of low-lying states in101Mo

The properties of the triplet of low-lying states in¹⁰¹Mo have been studied through spectroscopy of theγ radiation following thermal neutron capture in¹⁰⁰Mo and β^? decay of¹⁰¹Nb and through a measurement of the proton angular distributions in the¹⁰⁰Mo(d,p) reaction with 14 MeV deuteron energy. The half-lives of the 13.5 keV state and the 57.0 keV 5/2⁺ state have been measured as 226(7) and 133(7)ns, respectively. These values and the quadrupole/dipole mixing ratios of the 13.5 keV and 43.5 keV transitions yield spin and parity 3/2⁺ for the 13.5 keV level. The E2 components in the 13.5 (3/2⁺ →1/2⁺) and 43.5 keV (5/2⁺→3/2⁺) transitions are ≦ 8·10^?4 and 54(9)%, respectively. The possibility of an additional state near to the 57.0 keV level is discussed. IBFM/PTQM calculations, taking into consideration the transitional character of the¹⁰⁰Mo boson core, account for the electromagnetic-transition and transfer-reaction pattern of the triplet of states.     

Distribution of Triplet Separators in Bacterial Genomes

Distributions of triplet separator lengths for two bacterial complete genomes are analyzed. The theoretical distributions for the independent random sequence and the first-order Markov chain are derived and compared with the distributions of the bacterial genomes. A prominent double band structure, which does not exist in the theoretical distributions, is observed in the bacterial distributions for most triplets.``