The electronic structure of boron-hydrogen complex and boron pair in diamond are studied by first-principles density-functional calculations with supercell models. The electronic structure calculated for the B-H complexes with C2v or C3v symmetry and the nearest-neighbor B pair is used to interpret recent experimental results such as B 1s x-ray photoemission spectroscopy, 11B nuclear quadruple ...

A new and simple method followed by atomic absorption spectrometry has been developedfor indirect determination of ascorbic acid (AA). The proposed method was based on the oxidationof AA to dehydroascorbic acid with Cu2+cation(200mgL-1)in an ammonium thiocyanatesolution atpH2.4. AA reduces Cu2+to Cu+followed by the precipitation of Cu+ with SCN-. Then, the excess ofCu2+in the solution was measu...

We analyze optical soliton propagation in the presence of weak absorption lines with much narrower linewidths as compared to the soliton spectrum width using the novel perturbation analysis technique based on an integral representation in the spectral domain. The stable soliton acquires spectral modulation that follows the associated index of refraction of the absorber. The model can be applied...

Atomic absorption spectroscopy Atomic absorption spectroscopy (AAS) was developed in the early 1950’s by Alan Walsh. It works on the principle that certain elements absorb certain wavelengths, and this level of absorption is characteristic of each element. Also, electrons in atoms can only exist in particular energy levels, and when an electron moves to a higher energy level, electromagnetic ra...

Motion in the microcosm unfolds via the formation of wavepackets, resulting from a coherent superposition of quantum states. Pioneered by A. H. Zewail, nuclear motion in (bio-)molecules as well as the formation and rupture of chemical bonds have been accessed extensively by femtosecond (1 fs = 10 seconds) pump-probe spectroscopy. For these outstanding experiments, A. H. Zewail was awarded the N...