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Hg crystallizes in the orthorhombic Cmce space group. The structure is two-dimensional and consists of two Hg sheets oriented in the (1, 0, 0) direction. Hg is bonded in a 1-coordinate geometry to three equivalent Hg atoms. There are one shorter (3.24 Å) and two longer (3.35 Å) Hg–Hg bond lengths.
Isomeric states and associated collective structures have been studied up to high spin in 198,200,202 Hg using multinucleon transfer reactions and the Gammasphere array. A coupled rotational band, with possible four-quasiparticle character, is established in 198 Hg. Sequences built on two-quasiparticle, positive- and negative-parity levels are assigned to 202 Hg. New isomers in 202 Hg with I π = (7 – ) and (9 – ), and T 1/2 = 10.4(4) ns and 1.4(3) ns, respectively, have been identified. A half-life of 1.0(3) ns is established for the I π = 12 + state in 200 Hg. B(E2) values deduced from isomeric transitions in Hg isotopes indicate that, while collectivity near the ground state gradually diminishes from N = 112 to N = 124, it is found to increase for the 12 + and 9 – states up to N = 118, followed by a reduction for higher neutron numbers. Calculations using the ultimate cranker code provide insight into the variation of deformation with spin and allow for an understanding of observed band crossings. As a result, the evolution of collectivity with spin, and along the isotopic chain, is described.
Understanding the experimental conditions necessary for the development of radial and axial compositional homogeneity in directionally solidified Hg(0.89)Mn(0.11)Te(MMT) crystals has been difficult due to the lack of segregation coefficient data on the Hg(1-x)Mn(x)Te alloy system in the X = 0 to 0.3 composition range. Determining segregation coefficient data from the available Hg(1-x)Mn(x)Te alloy phase equilibria data is not practical due to discrepancies in the shape of the reported solidus and liquidus curves in the X = 0 to 0.3 range. To resolve these discrepancies and to obtain segregation coefficient data which can be used to understand homogeneity in directionally solidified MMT crystals, the solidus and liquidus temperatures of seven Hg(1-x)Mn(x)Te alloys in the X = 0 to 0.3 range were determined using differential thermal analysis (DTA). The Hg(1-x)Mn(x)Te phase diagram constructed for the X = 0 to 0.3 range of this alloy system from the DTA measurements clarifies the shape of the solidus and liquidus curves in this range. The segregation coefficient for the Hg(1-x)Mn(x)Te system was found to vary from 5 to 4.4 as the solidus composition increased from 0-30 atomic percent MnTe. This information will be useful in the analysis of axial and radial homogeneity of directionally solidified MMT crystals.
Savannah River Site (SRS) and Oak Ridge National Laboratory (ORNL) were both major material production sites for the U.S.'s nuclear program during the 20. century. Both sites discharged mercury (Hg) to streams. Oak Ridge streams have accumulated significant levels of Hg from early 'historical' discharges. Diffusive Gradient in Thin Films (DGT) samplers may be a labor and material saving method to monitor the Hg contamination of streams at both sites. Humic and Fulvic acids are released during the degradation of plant and animal residue. They are part of the Dissolved Organic Matter that colors the black water streams of the southern U.S.. Humic acid and Fulvic acids have a tendency to sequester heavy metals, like Hg, and may interfere with the reactions needed to draw the Hg through the thin films of the DGT samplers. Project Objective: Use a UV-Vis spectrophotometer to estimate the levels of Dissolved Organic Carbon (DOC) in the streams selected to test the effect of DOC on DGT samplers. Conclusion: UV-Vis is a convenient way to estimate the amount of DOC in streams and may be used to provide more context in DGT Hg sampling. efforts. Future Work: Analyze data from SRS and ORNL DGT samples; Compare the results of the DGT samplers with more traditional speciating methods from ORNL; Use a TOC Spectrophotometer to gain a more accurate picture of stream DOC.
Hg(SbS2)2(SbS2)2 is Stibnite-derived structured and crystallizes in the monoclinic C2/c space group. The structure is two-dimensional and consists of two Hg(SbS2)2 sheets oriented in the (1, 0, 0) direction and two SbS2 sheets oriented in the (1, 0, 0) direction. In each Hg(SbS2)2 sheet, there are two inequivalent Hg2+ sites. In the first Hg2+ site, Hg2+ is bonded in a distorted linear geometry to six S2- atoms. There are a spread of Hg–S bond distances ranging from 2.38–3.44 Å. In the second Hg2+ site, Hg2+ is bonded in a distorted linear geometry to six S2- atoms. There are a spread of Hg–S bond distances ranging from 2.38–3.45 Å. There are two inequivalent Sb+3.50+ sites. In the first Sb+3.50+ site, Sb+3.50+ is bonded to five S2- atoms to form edge-sharing SbS5 square pyramids. There are a spread of Sb–S bond distances ranging from 2.49–2.94 Å. In the second Sb+3.50+ site, Sb+3.50+ is bonded to five S2- atoms to form edge-sharing SbS5 square pyramids. There are a spread of Sb–S bond distances ranging from 2.49–2.94 Å. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded in a 5-coordinate geometry to two equivalent Hg2+ and three Sb+3.50+ atoms. In the second S2- site, S2- is bonded in a distorted trigonal non-coplanar geometry to one Hg2+ and two equivalent Sb+3.50+ atoms. In the third S2- site, S2- is bonded in a 5-coordinate geometry to two equivalent Hg2+ and three Sb+3.50+ atoms. In the fourth S2- site, S2- is bonded in a distorted trigonal non-coplanar geometry to one Hg2+ and two equivalent Sb+3.50+ atoms. In each SbS2 sheet, there are two inequivalent Sb+3.50+ sites. In the first Sb+3.50+ site, Sb+3.50+ is bonded to five S2- atoms to form distorted edge-sharing SbS5 square pyramids. There are a spread of Sb–S bond distances ranging from 2.50–3.00 Å. In the second Sb+3.50+ site, Sb+3.50+ is bonded to five S2- atoms to form distorted edge-sharing SbS5 square pyramids. There are a spread of Sb–S bond distances ranging from 2.50–3.02 Å. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded in a 3-coordinate geometry to two equivalent Sb+3.50+ and one S2- atom. The S–S bond length is 2.08 Å. In the second S2- site, S2- is bonded in a 3-coordinate geometry to three equivalent Sb+3.50+ atoms. In the third S2- site, S2- is bonded in a 3-coordinate geometry to two equivalent Sb+3.50+ and one S2- atom. In the fourth S2- site, S2- is bonded in a 3-coordinate geometry to three equivalent Sb+3.50+ atoms.
Hg is alpha structured and crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Hg is bonded in a 6-coordinate geometry to six equivalent Hg atoms. All Hg–Hg bond lengths are 3.18 Å.
Hg is alpha Po structured and crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Hg is bonded to six equivalent Hg atoms to form a mixture of corner and edge-sharing HgHg6 octahedra. The corner-sharing octahedral tilt angles are 0°. All Hg–Hg bond lengths are 3.16 Å.
Hg is Tungsten structured and crystallizes in the cubic Im-3m space group. The structure is three-dimensional. Hg is bonded in a distorted body-centered cubic geometry to eight equivalent Hg atoms. All Hg–Hg bond lengths are 3.40 Å.
Hg is alpha Po-like structured and crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Hg is bonded to six equivalent Hg atoms to form a mixture of edge and corner-sharing HgHg6 octahedra. The corner-sharing octahedral tilt angles are 0°. All Hg–Hg bond lengths are 3.20 Å.
Hg is alpha-like structured and crystallizes in the tetragonal I-42d space group. The structure is three-dimensional. Hg is bonded in a 6-coordinate geometry to six equivalent Hg atoms. There are four shorter (3.39 Å) and two longer (3.40 Å) Hg–Hg bond lengths.
Hg is beta Sn structured and crystallizes in the tetragonal I4_1/amd space group. The structure is three-dimensional. Hg is bonded to six equivalent Hg atoms to form a mixture of distorted corner and edge-sharing HgHg6 pentagonal pyramids. There are four shorter (3.21 Å) and two longer (3.28 Å) Hg–Hg bond lengths.
We discuss a design for a space based atomic frequency standard (AFS) based on Hg(sup +) ions confined in a linear ion trap. This newly developed AFS should be well suited for space borne applications because it can supply the ultra-high stability of a H-maser but its total mass is comparable to that of a NAVSTAR/GPS cesium clock, i.e., about 11kg. This paper will compare the proposed Hg(sup +) AFS to the present day GPS cesium standards to arrive at the 11 kg mass estimate. The proposed space borne Hg(sup +) standard is based upon the recently developed extended linear ion trap architecture which has reduced the size of existing trapped Hg(sup +) standards to a physics package which is comparable in size to a cesium beam tube. The demonstrated frequency stability to below 10(sup -15) of existing Hg(sup +) standards should be maintained or even improved upon in this new architecture. This clock would deliver far more frequency stability per kilogram than any current day space qualified standard.
Idaho National Laboratory’s (INL) FX Hg fixative solution was deployed at the Y-12 Complex in Oak Ridge, Tennessee to support disposal of mercury-contaminated metal debris. The fixative was dispensed via fogging. Fogging infiltrates non-line-of-sight areas improving fixative coating on complex geometries such as debris piles. FX Hg is the mercury vapor controlling derivative of INL’s FX2 fixative. FX2 was jointly developed with the National Nuclear Laboratory of the United Kingdom, and INL developed the FX Hg derivative to suppress mercury vapor generation. The Y-12 deployment was performed in concert with cleanup contractor UCOR. A dumpster filled with debris was fogged with FX Hg. The material was acceptable as municipal landfill waste, save for the mercury vapor levels measured. If the mercury vapor generation rate could be sufficiently reduced, disposal costs for this waste would be dramatically reduced. FX Hg had previously proven effective at significantly reducing mercury vapor generation rates in bench scale testing at INL. This deployment was the first field scale deployment of the method. Efficacy results were underwhelming, but interpretation of the outcome is complicated by a paucity of hard data. Methods for improving data capture and analysis are analyzed. Operational difficulties associated with scaling the process up and process improvements for future deployments are discussed.
Male rats (260-285 gm) were exposed to 100% oxygen at 450 or 600 mm Hg for 1 to 4 days. Rats maintained at 450 mm Hg ate 92% the amount of food eaten by ad libitum controls maintained at sea level conditions. At 600 mm Hg, the food intake was 77% of the ad libitum controls. No difference was found in the plasma level of glucose, free fatty acids, and corticosterone between oxygen exposed rats and their respective pair-fed controls. The in vitro conversion of acetate into fatty acids by adipose tissue from rats exposed at 450 mm Hg for 2, 3, or 4 days was significantly increased above pair-fed controls and ad libitum controls. Increasing the oxygen pressure to 600 mm Hg abolished this increase, and in fact, reversed the increased synthesis to a significant decrease for the 4-day exposure.
An experimental double-probe technique is described which allows the He(+) ion density to be measured directly as a function of time in the afterglow of a helium-metal-vapor discharge. As an application example, two CW laser transitions of the He-Hg(+) laser at 6150 and 7944 A are considered which both arise from excited 7p (2) P terms of Hg II. The time-resolved double-probe technique is used to measure the destruction rate of the He(+) ion density, which is then compared with the spontaneous-emission decay rate for 7p (2) P terms of Hg II. The results obtained show unambiguously and directly that the dominant excitation process for the two transitions considered is a charge-transfer collisional reaction of the form He(+) plus Hg yields He plus metastable Hg(+) plus the energy defect for this reaction. It is noted that the time-resolved double-probe technique may provide a simple method for measuring ion mobilities in a multi-ion plasma.
An abundance analysis has been conducted of 21 elements in 21 Hg-Mn, two Si-Cr, and six normal stars using model atmospheres and high-dispersion spectroscopy in the visible and UV. Manganese line strengths imply abundances that correlate well with stellar effective temperature. Within the studied sample of Hg-Mn stars there appears to be no correlation of abundances of any element with projected rotational velocity. Abundances in several Hg-Mn stars show patterns that are probably consistent with diffusion but difficult to reconcile with equilibrium nucleosynthesis. In general, no combination of gross stellar physical parameters is sufficient to characterize the patterns of line strengths observed in Hg-Mb Hg-Mn stars.
Single crystal samples of phosphorus doped Hg sub 0.8 Cd sub 0.2 Te were anneald at temperatures varying from 450 C to 600 C in various Hg atmospheres. The samples were quenched to room temperature from the annealing temperatures. Hall effect and mobility measurements were performed at 77 K on all these samples. The results indicate the crystals to be p type for a total phosphorus concentration of 10 to the 19th power/cu cm in all the samples. The hole concentration at 77 K increases with increasing Hg pressures at 450 C and 500 C contrary to the observation in undoped crystals. Also, at low Hg pressures the concentration of holes in the phosphorus doped crystals is lower than in the undoped crystals. The hole concentration in all the samples is lower than the intrinsic carrier concentration at the annealing temperatures. The hole mobility in the doped crystals is similar to that in the undoped crystals. A defect model according to which phosphorus behaves as a single acceptor interstitially, occupying Te lattice sites while it acts as a single donor occupying Hg lattice sites was established. Equilibrum constants established for the incorporation of all the phosphorus species explain the experimental results
Single crystal samples of undoped and doped Hg sub 1-x Cd sub x Te were annealed at varying temperatures and partial pressures of Hg. Hall effect and mobility measurements were carried out on these samples after quenching to room temperature. Based on the variation of the carrier concentration and the carrier mobility as a function of the partial pressure of Hg temperature, and dopant concentration, defect models were established for the doped and the undoped crystals. These models indicate that the native acceptor defects in both Hg0.8Cd0.2Te and Hg0.6Cd0.4Te doubly ionized and the native donor defects are negligible in concentration, implying that p to n conversion in these alloys occurs due only to residual donors. Incorporation mechanism of copper, indium, iodine, and phosphorus were investigated. A large concentration of indium is found to be paired with the native acceptor defects. Results on crystals doped with phosphorus indicate that phosphorus behaves amphoterically, acting as a donor on Hg lattice sites and as an acceptor intersitially on Te lattice sites. A majority of the phosphorus is found to be present as neutral species formed from the pairing reaction between phosphorus on Hg lattice sites and phosphorus in interstitial sites. Equilibrium constants for the intrinsic excitation reaction, as well as for the incorporation of the different dopants and the native acceptor defects were established.