The crystal and molecular structure of a new polymorph of carbonylhydridotris(triphenylphosphine)rhodium(I) having a Rh-H stretching absorption at 2013 cm−1

A new polymorph of HRh(CO)(PPh₃)₃, with a Rh-H of 2013 cm^–1, has been isolated by crystallization fromtert-butyl methyl ether/tetrahydrofuran. The crystals are monoclinic (space groupP2₁/n), witha=21.48(2) Å,b=14.92(2)Å,c=14.52(1)Å,=107.95(8)°. A finalR value of 0.065 was obtained using 2243 reflections which hadI _net>2.5(I _net). The structure of the new polymorph has a similar coordination geometry to the known polymorph, but a different conformation of one of the phenyl rings.     

Ballistic and localized transport for the atom optics kicked rotor in the limit of a vanishing kicking period

We present mean energy measurements for the atom optics kicked rotor as the kicking period tends to zero. A narrow resonance is observed marked by quadratic energy growth, in parallel with a complete freezing of the energy absorption away from the resonance peak. Both phenomena are explained by classical means, taking proper account of the atoms' initial momentum distribution.     

Error analysis of a practical energy density sensor

The investigation of an active control system based on acoustic energy density has led to the analysis and development of an inexpensive three-axes energy density sensor. The energy density sensor comprises six electret microphones mounted on the surface of a 0.025-m (1 in.) radius sphere. The bias errors for the potential, kinetic, and total energy density as well as the magnitude of intensity of a spherical sensor are compared to a sensor comprising six microphones suspended in space. Analytical, computer-modeled, and experimental data are presented for both sensor configurations in the case of traveling and standing wave fields, for an arbitrary incidence angle. It is shown that the energy density measurement is the most nearly accurate measurement of the four for the conditions presented. Experimentally, it is found that the spherical energy density sensor is within +/- 1.75 dB compared to reference measurements in the 110-400 Hz frequency range in a reverberant enclosure. The diffraction effects from the hard sphere enable the sensor to be made more compact by a factor of 3 compared to the sensor with suspended microphones.