– The energy spectrum of the quantum Klein-Gordon (KG) lattice is computed numerically for some model parameters that are relevant for optical phonon spectra. A pairing of the phonon states is found when the nonlinearity is significant which agrees with other studies on different quantum lattice models [1,2]. It results from the anharmonic energy contribution the magnitude of which is quantifie...

Optical absorption spectra of higher fullerenes (C70 and C76) as well as of C60 are calculated by a tight binding model with a long range Coulomb interaction. A reasonable parameter set gives calculated spectra which are in overall agreement with the experiments of of C60 and C70 in solutions. The variations of the spectral shape are discussed relating with the symmetry reduction going from C60...

A short review of ultra-compact binaries, focused on ultra-compact X-ray binaries, is followed by a discussion of recent results of our VLT campaign to obtain optical spectra of (candidate) ultra-compact X-ray binaries. We find evidence for carbon/oxygen as well as helium/nitrogen discs and no evidence for (traces) of hydrogen. This suggests that the donors in the observed systems are white dwa...

We present accurate measurements of the central wavelengths of 4947 atomic absorption lines in the solar optical spectrum. The wavelengths, precise to a level ∼ 50 − 150 m s −1 , are given for both flux and disc-centre spectra, as measured in relatively recent FTS solar atlases. This catalogue modernizes existing sources based on photographic measurements and provides a benchmark to test and pe...

UV-vis optical absorption spectra of the antitrypanocidal drug benznidazole solvated in water were measured for various concentrations. The spectra show a prominent peak around 3.80 eV, while deconvolution of the UV-vis optical absorption spectra revealed six bands centered at 3.60, 3.83, 4.15, 4.99, 5.60, and 5.76 eV. Benznidazole electronic transitions were obtained after density functional t...

The study of electronic excitations in hydrogen terminated silicon clusters is important for understanding the optical properties of confined systems such as quantum dots and porous silicon. Here we calculate the excitation energies and absorption spectra for SinHm clusters using linear response theory within the time-dependent local density approximation (TDLDA). We find the computed excitatio...

I review recent optical observations of supernovae (SNe) conducted by my group. The Lick Observatory Supernova Search with the 0.76-m Katzman Automatic Imaging Telescope is currently the world’s most successful search for nearby SNe. We also use this telescope to obtain multicolor light curves of SNe. One of the more interesting SNe we discovered is SN 2000cx, which differs from all previously ...

We have developed a numerical scheme for exact diagonalization of the few-particle electron–hole interaction Hamiltonians with a simultaneous resolution of several discrete conserved quantum numbers such as total electron or hole spins, total angular momentum, or parity. The method was applied to a simple model of a two-dimensional rectangular quantum box of arbitrary size and anisotropy, and c...

The influence of the normal mode rotation (i.e. the Duschinsky mixing) on the molecular electronic spectra in polyatomic molecules is treated by means of multidimensional intramolecular distributions (MID). It is shown that symmetry properties of the two-dimensional MID which relate emission and absorption spectra or pertain to the exchange of modes do not exist if the number of non-separable m...

In this work, a comprehensive methodology for the fitting of single-walled carbon nanotube absorption spectra is presented. Different approaches to background subtraction, choice of line profile, and calculation of full width at half-maximum are discussed both in the context of previous literature and the contemporary understanding of carbon nanotube photophysics. The fitting is improved by the...