Chemical Constraints on the Water and Total Oxygen Abundances in the Deep Atmosphere of Saturn

Thermochemical equilibrium and kinetic calculations for the trace gases CO, PH3, and SiH4 give three independent constraints on the water and total oxygen abundances of Saturn's deep atmosphere. A lower limit to the water abundance of H2O/H2 > 1.7 x 10^-3 is given by CO chemistry while an upper limit of H2O/H2 < 5.5 x 10^-3 is given by PH3 chemistry. A combination of the CO and PH3 constraints indicates a water enrichment on Saturn of 1.9 to 6.1 times the solar system abundance (H2O/H2 = 8.96 x 10^-4). The total oxygen abundance must be at least 1.7 times the solar system abundance (O/H2 = 1.16 x 10^-3) in order for the SiH4 to remain below a detection limit of SiH4/H2 < 2 x 10^-10. A combination of the CO, PH3, and SiH4 constraints suggests that the total oxygen abundance on Saturn is 3.2 to 6.4 times the solar system abundance. Our results indicate that oxygen on Saturn is less enriched than other heavy elements (such as C and P) relative to a solar system composition. This work was supported by NASA NAG5-11958.Comment: 19 pages, 2 figures, accepted for publication in the Astrophysical Journa

Comment on "Peierls Gap in Mesoscopic Ring Threated by a Magnetic Flux"

In a recent letter, Yi et al. PRL 78, 3523 (1997), have considered the stability of a Charge Density Wave in a one-dimensional ring, in the presence of an Aharonov-Bohm flux. This comment shows that, in one dimension, the stability of the Charge Density Wave depends on the parity of the number of electrons in the ring. This effect is similar to the parity effect known for the persistent current in one-dimensional rings.Comment: Latex, 1 page, 2 figure

Calculating energy derivatives for quantum chemistry on a quantum computer

Modeling chemical reactions and complicated molecular systems has been proposed as the `killer application' of a future quantum computer. Accurate calculations of derivatives of molecular eigenenergies are essential towards this end, allowing for geometry optimization, transition state searches, predictions of the response to an applied electric or magnetic field, and molecular dynamics simulations. In this work, we survey methods to calculate energy derivatives, and present two new methods: one based on quantum phase estimation, the other on a low-order response approximation. We calculate asymptotic error bounds and approximate computational scalings for the methods presented. Implementing these methods, we perform the world's first geometry optimization on an experimental quantum processor, estimating the equilibrium bond length of the dihydrogen molecule to within 0.014 Angstrom of the full configuration interaction value. Within the same experiment, we estimate the polarizability of the H2 molecule, finding agreement at the equilibrium bond length to within 0.06 a.u. (2% relative error).Comment: 19 pages, 1 page supplemental, 7 figures. v2 - tidied up and added example to appendice

Device for multi phase and single phase contacting

A multiphase contacting stage is provided that includes a first rotatable disc having a hollow disc-shaped cavity, an input port and an output port, and a second rotatable disc, where the second rotatable disc has a channeled cavity, an input port and an output port, and is disposed in the hollow disc-shaped cavity of the first rotatable disc, where the first rotatable disc and said second rotatable disc are concentric about an axis, where the multiphase contacting stage operates to integrate centrifugal separation and countercurrent mass transfer of a material for separation

Device for multiphase and single phase contacting

A multiphase contacting stage is provided that includes a first rotatable disc having a hollow disc-shaped cavity, an input port and an output port, and a second rotatable disc, where the second rotatable disc has a channeled cavity, an input port and an output port, and is disposed in the hollow disc-shaped cavity of the first rotatable disc, where the first rotatable disc and said second rotatable disc are concentric about an axis, where the multiphase contacting stage operates to integrate centrifugal separation and countercurrent mass transfer of a material for separation