The path-integral technique and the large-quantum-number behaviour of energy eigenvalues of coupled anharmonic oscillators

Using the path-integral technique, we derive here the large-quantum-number behaviour of energy eigenvalues of a coupled anharmonic oscillator. The result clearly shows the behaviour of the leading and the next to leading term with respect to the parameters contained in the coupled anharmonic part of the potential.     

On the luminescence of TlCl+KCl phosphor

The measurements on the luminescence spectra of TlCl+KCl mixed phosphor under low energy cathode rays at 80° K have been presented here. The reflectance as well as excitation spectra of this mixed phosphors have also been studied. The X-ray diffraction studies of the samples along with the optical studies show that the mixed phosphor consists of two phases: (1) KCl:Tl (2) TlCl:K. It has been observed that the emission bands due to thallous chloride are gradually quenched with the increase in potassium chloride content of the phosphor; further, the emission bands supposed to be due to KCl:Tl phosphors gradually appear. Since some of the emission bands obtained with KCl:Tl phosphors at high thallium content are also present in the luminescence spectra of thallous chloride it is suggested that such bands should be attributed to undissociated thallous chloride present in KCl:Tl phosphor. The quenching of thallous chloride emission by the incorporation of potassium chloride in the system has been explained as being due to the absence of stoichiometric excess of thallium in such mixed system. The results also show that the absorption spectra of the mixed system is determined by the minor components KCl:Tl. This indicates that the absorption spectra of KCl:Tl phosphor should not be affected by the presence of undissociated thallous chloride.     

NMR spectral studies. XIV. Carbon-13 nuclear magnetic resonance studies on β-lactams

Carbon-13 NMR spectra of a variety of mono- and bicyclic β-lactams have been measured and the chemical shifts of the ring carbon atoms have been assigned unambiguously. Effects of substituents on the chemical shifts of these carbons are also discussed.     

Unwinding of DNA polymerases by the antitumor drug,cis-diamminedichloroplatinum(II)

The helix-turn-helix motifs of the DNA binding domains of human polymerase-alpha and polymerase-kappa are dramatically perturbed upon binding to cisplatin with concomitant release of zinc.     

Proposal for measurement of harmonic oscillator berry phase in ion traps

We propose a scheme for measuring the Berry phase in the vibrational degree of freedom of a trapped ion. Starting from the ion in a vibrational coherent state we show how to reverse the sign of the coherent state amplitude by using a purely geometric phase. This can then be detected through the internal degrees of freedom of the ion. Our method can be applied to preparation of entangled states of the ion and the vibrational mode.     

Karhunen-Loeve local characterization of spatiotemporal chaos in a reaction-diffusion system

By computing the Karhunen-Loeve decomposition (KLD) correlation length xi(KLD) of a reaction-diffusion system in the extensive chaos regime, we show that it is a sensitive measure of spatial dynamical inhomogeneities. It reveals substantial spatial nonuniformity of the dynamics at the boundaries and can also detect slow spatial variations in system parameters. The intensive length xi(KLD) can be easily computed from small local subsystems and is found to have a similar parametric dependence as the two-point correlation length computed over the full system size.     

Studies on lactams—XX Stereochemistry of some penicillin sulfoxides and analogs from lanthanide induced shifts

Lanthanide induced shifts have been shown to provide reliable information on the steric disposition of protons in the vicinity of the sulfoxide group in penicillin derivatives and analogs. Because of its dipolar nature the sulfoxide bond serves as a favored site for complex formation with the lanthanide. The configuration of several penam sulfoxides and the conformation of the thiazolidine ring of one of them have been deduced.