In search of photon’s elementary axial magnetostatic field

 Experimental investigations of the photon’s B ⁽³⁾-field (third longitudinal polarization) are reported. The existence of an “axial magnetostatic field of photon” has been predicted in B _π or B ⁽³⁾-theory as the fundamental property of the circularly polarized light, and reported in numerous papers and monographs. High-sensitivity detection has been employed in photomagnetic induction, Faraday, and inverse Faraday effects (IFE) originating from such a field. The results of all three experiments clearly disprove the claims of B _π-theory. Putting together these results and theoretical calculations in perspective, it is concluded that such fields are non-existent. Received: 25 January 1996 / Revised version: 24 May 1996     

Vapor sensing using polymer/carbon black composites in the percolative conduction regime

To investigate the behavior of chemiresistive vapor sensors operating below or around the percolation threshold, chemiresistors have been formed from composites of insulating organic polymers and low mass fractions of conductive carbon black (CB, 1-12% w/w). Such sensors produced extremely large relative differential resistance changes above certain threshold vapor concentrations. At high analyte partial pressures, these sensors exhibited better signal/noise characteristics and were typically less mutually correlated in their vapor response properties than composites formed using higher mass fractions of CB in the same set of polymer sorption layers. The responses of the low-mass-fraction CB sensors were, however, less repeatable, and their nonlinear response as a function of analyte concentration required more complicated calibration schemes to identify and quantify analyte vapors to compensate for drift of a sensor array and to compensate for variability in response between sensor arrays. Because of their much larger response signals, the low-mass-fraction CB sensors might be especially well suited for use with low-precision analog-to-digital signal readout electronics. These sensors serve well as a complement to composites formed from higher mass fractions of CB and have yielded insight into the tradeoffs of signal-to-noise improvements vs complexity of signal processing algorithms necessitated by the use of nonlinearly responding detectors in array-based sensing schemes.     

Theoretical study on the (O2-HF) complex

The potential energy surface of the (O₂-HF)⁺ complex has been investigated theoretically. Equilibrium structure has been calculated at the UCCSD/6-311++G(2d,2p) and UCCSD/aug-cc-pVTZ levels of theory. Two stable complexes, T-shape and collinear, have been found on the surface whose interaction energies are calculated to be −12.36 and −10.19 kcal mol⁻¹, respectively, at the UCCSD(T)/aug-cc-pVTZ level after correcting for the basis set superposition error (BSSE). Natural bond orbital (NBO) analysis revealed intermolecular charge transfers occur followed by intramolecular charge rearrangement. A large contribution from the n_F to π* _OO is found.     

Cerium dioxide thin film optical waveguides

Cerium dioxide thin film optical waveguides were fabricated by an RF magnetron sputtering process. The films were deposited on glass substrates and on silicon dioxide layers grown on silicon substrates. Optical loss measurements for the fabricated waveguides are reported. It is seen that the volume losses in the films were fairly high compared with the surface losses.     

Characterisation of the Breaking Force of Latex Particle Aggregates by Micromanipulation

The breaking force of single polystyrene latex aggregates has been measured by micromanipulation. Aggregates were made by mixing primary particles at their isoelectric point using a vortex mixer or Brownian motion. The aggregates made by the former method had a mean breaking force of 51±3 μN, whilst those by the latter had a mean breaking force of 5.3±0.5 μN for samples taken at aggregation times of 20 min to 6 h. This clearly demonstrates that the micromanipulation technique is suitable for characterising the breaking force of particle aggregates made under different aggregation conditions, and that the way collisions of primary particles were created had a significant impact on the breaking force of the aggregates.     

A parallel multi-configuration self-consistent field algorithm

A scalable multi-configuration self-consistent field (MCSCF) algorithm is described. The method for optimizing the orbital and configurational parameters is based upon the two-step Newton–Raphson approach with an augmented orbital Hessian matrix. A single copy of the two-electron integrals in the molecular orbital basis is distributed over the memory of all processors. Storage of the augmented Hessian is avoided by re-computing its elements as needed. A replicated data approach is used to parallelize the configuration interaction step. Scalability to 1024 processors is demonstrated.