Flavin- and Deazaflavin-Containing Model Compounds Mimic the Energy Transfer Step in Type-II DNA-Photolyases

A distinct energy transfer between the deazaflavin and the flavin is observed in compounds that mimic the DNA repair function of DNA-photolase enzymes (see sketch). Studies on these models prove that the deazaflavin acts solely as photoantenna and suggest that the two cofactors have to be separated within the enzyme to suppress a competitive intercofactor electron transfer reaction.     

Polycephalin B and C: Unusual Tetramic Acids from Plasmodia of the Slime Mold Physarum polycephalum (Myxomycetes)

Illumination results in increased formation of metabolites 1 and 2 in the plasmodia of the slime mold Physarum polycephalum. This was determined from HPLC studies undertaken in the search for the photoactive substances involved in the “blue-light phenomenon”. The isolation and structure elucidation of 1 and 2 is described.     

A Self‐Assembling Polythiophene Functionalised with a Cysteine Moiety

A new copolymer bearing a cysteine moiety, designed for molecular interaction, metal‐ion detection, and chiral recognition, was synthesised starting from the dibromo derivative of methyl N‐(tert‐butoxycarbonyl)‐S‐thien‐3‐ylcysteinate and distannylthiophene through a Stille coupling reaction. UV‐vis spectroscopy, circular dichroism, NMR spectroscopy, and gel permeation chromatography analyses evidenced that this polymer is able to form self‐assembling structures, through the formation of a hydrogen‐bond network, not only in the solid state but also in solution.

     

Transient Dynamics of Light Propagation in A-Atom EIT Medium

We investigate the transient phenomenon or property of the propagationof an optical probe field in a medium consisting of many A-type three-level atoms coupled to this probe field and a classical driven field. We observe a hidden symmetry and obtain an exact solution for this light propagation problem by means of the spectral generating method. This solution enlightens us to propose a practical protocol implementing the quantum memory robust for quantum decoherence in a crystal. As a transient dynamic process this solution also manifests an exotic result that a wave-packet of light will split into three packets propagating at different group velocities. It is argued that “super-luminal group velocity“ and “sub-luminal group velocity“ can be observed simultaneously in the same system. This interesting phenomenon is expected to be demonstrated experimentally.     

Energies of 1s2ng and 1s2nh (n = 5, 6, 7, and 8) States for Lithium Isoelectronic Sequence

The nonrelativistic energies for lithium isoelectronic sequence 1s²ng and 1s²nh (n=5, 6, 7, and 8) states from Z=3 to 8 are calculated by using a full core plus correlation (FCPC) method with multiconfiguration interaction wave functions. Relativistic and mass-polarization effects on the energy are evaluated as the first-order perturbation theory. Our predicted excitation energies are compared with previous experimental results in the literature.     

模拟 ps激光驱动的类氖锗19.6 nm X光激光

 瞬态电子碰撞激发产生X光激光的机制可以极大减少X光激光的泵浦能量。模拟了脉宽为1 ps,波长1.053 μm的钕玻璃激光驱动的类氖锗X光激光。模拟表明,在临界面附近可以产生高达60 cm ^-1的增益,还计算了X光激光在等离子体中的传播,计算表明X光激光在等离子体中的折射效应仍然是影响X光激光输出强度及分布的重要因素。