Opacities of S-type Stars: The Singlet B 1 Π–X 1 Σ + , B 1 Π–A 1 △, and C 1 Σ + –X 1 Σ + Band Systems of ZrO
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Peter F. Bernath↗
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Rates of the reactions of 1, 1, 1-trichloroethane /methyl chloroform/ and 1, 1, 2-trichloroethane with OH
Highly purified samples of the two chlorocarbons, trichloroethane and methyl chloroform, were reacted with OH over the temperature range of 278 to 460 K in a discharge-flow system with resonance flourescence detection of OH. Attention is given to the data obtained at various temperature levels and to the graph of Arrhenius' diagram. It is determined that the methyl chloroform reaction was slower and its temperature dependence somewhat steeper than the earlier measurements had indicated, probably due to the presence of faster reacting olefinic impurities in prior studies. Implications for stratospheric ozone reductions by C10-sub-x catalysis and for tropospheric OH-budget are briefly discussed.
Jeong, K.-M.↗
Theoretical Treatment of the X(sup 1)Sigma(sup +), A(sup 1)Sigma(sup +), and B(sup 1)Pi states of LiH
Ab initio self-consistent-field plus configuration-interaction calculations are reported for the X(sup 1)Sigma(sup +), A(sup 1)Sigma(sup +), and B(sup 1)Pi states of LiH using a 22(sugma)12(pi)7(delta) function Slater basis set. The resulting dissociation energies, with the experimental values in parentheses, are D(sub e)(X(sup 1)Sigma(sup +)) = 19 972 (20288)/ cm, and D(sub e)(A(sup 1)Sigma(sup +)) = 9042 (8682)/ cm, and D(sup e)(B(sup 1)Pi) = 284 (288) /cm. This is the first ab initio treatment to quantitatively account for the binding in the B(sup 1)Pi state. Calculated dipole moments and electronic transition moments for the X(sup 1)Sigma(sup+)-A(sup 1)Sigma(sup +), X(sup 1)Sigma(sup +)-B((sup 1)Pi, and A(sup 1)Sigma(sup +)- B(sup 1)PI band systems are in excellent agreement with existing theoretical and experimental data. Radiative transition probabilities and lifetimes, including both the bound-bound and bound-free contributions, are computed for all vibrational levels of the A(sup 1)Sigma(sup+) and B(sup 1)Pi states. Comparison with previous results using experimentally based potentials provides insight into the sensitivity of the radiative lifetimes to the detailed nature of the uppermost region of the potentials. Our calculated lifetimes for the lower vibrational levels of the A(sup 1)Sigma(sup +) state are within the experimental uncertainty. Our calculated lifetimes for the three vibrational levels of the B(sup 1)Pi state are in excellent agreement with those of Zemke and Stwalley (values in parentheses), increasing with (upsilon)' from 11.3 (11.3) nsec at (upsilon)' = 0, to 17.0 (17.0) nsec at (upsilon)' = 1, and then to 23.5 (24.0) nsec at (upsilon)' = 2.
Partridge, Harry↗
Substituted 1,1,1-triaryl-2,2,2-trifluoroethanes and processes for their synthesis
Synthetic procedures are disclosed for tetraalkyls, tetraacids, and dianhydrides substituted 1,1,1-triaryl 2,2,2-trifluoroethanes which comprises: (1) 1,1-bis (dialkylaryl) 1-aryl 2,2,2-trifluoroethane, (2) 1,1-bis (dicarboxyaryl) 1-aryl 2,2,2-trifluoroethane, or (3) cyclic dianhydride or diamine of 1,1-bis (dialkylaryl) 1-aryl 2,2,2-trifluoroethanes. The synthesis of (1) is accomplished by the condensation reaction of an aryltrifluoromethyl ketone with a dialkylaryl compound. The synthesis of (2) is accomplished by the oxidation of (1). The synthesis dianhydride of (3) is accomplished by the conversion of (2) to its corresponding cyclic dianhydride. The synthesis of the diamine is accomplished by the similar reaction of an aryltrifluoromethyl ketone with aniline or aklyl substituted or disubstituted anilines. Also, other derivatives of the above are formed by nucleophilic displacement reactions.
Alston, William B.↗
Substituted 1,1,1-triaryl 2,2,2-trifluoroethanes and processes for their synthesis
Synthetic procedures to tetraalkyls, tetraacids, and dianhydrides substituted 1,1,1-triaryl 2,2,2-trifluoroethanes which comprises: (1) 1,1-bis(dialkylaryl) 1-aryl-2,2,2-trifluoroethane, (2) 1,1-bis(dicarboxyaryl) 1-aryl-2,2,2-trifluoroethane, or (3) cyclic dianhydride or diamine of 1,1-bis(dialkylaryl) 1-aryl-2,2,2-trifluoroethanes. The synthesis of (1) is accomplished by the condensation reaction of an aryltrifluoromethyl ketone with a dialkylaryl compound. The synthesis of (2) is accomplished by oxidation of (1). The synthesis dianhydride of (3) is accomplished by the conversion of (2) to its corresponding cyclic dianhydride. The synthesis of the diamine is accomplished by the similar reaction of an aryltrifluoromethyl ketone with aniline or alkyl substituted or disubstituted anilines. Also, other derivatives of the above are formed by nucleophilic displacement reactions.
Alston, William B.↗
Substituted 1,1,1-triaryl-2,2,2-trifluoroethanes and processes for their synthesis
Synthetic procedures are given for tetraalkyl, tetraacid and dianhydrides substituted 1,1,1-triaryl-2,2,2-trifluoroethanes which comprises: (1) 1,1-bis (dialkylaryl) 1-aryl-2,2,2 trifluoroethane; (2) 1,1-bis (dicarboxyaryl) 1-aryl-2,2,2 trifluoroethane; or (3) cyclic dianhydride or diamine of 1,1-bis (dialkylaryl) 1-aryl-2,2,2 trifluoroethanes. The synthesis of (1) is accomplished by the condensation reaction of an aryltrifluoromethyl ketone with a dialkylaryl compound. The synthesis of (2) is accomplished by oxidation of (1). The synthesis dianhydride of (3) is accomplished by the conversion of (2) to its corresponding cyclic dianhydride. The synthesis of the diamine is accomplished by the similar reaction of an aryltrifluoromethyl ketone with aniline or alkyl substituted or disubstituted anilines. Also, other derivatives of the above are formed by nucleophilic displacement reactions.
Alston, William B.↗
Hepatic pathology in mice after continuous inhalation exposure to 1, 1, 1-trichloroethane
Mice exposed to either 250ppm or 1,000ppm 1,1,1-trichloroethane in air continuously for 14 weeks demonstrated significant changes in the centrilobular hepatocytes for the 1,000ppm group. Moderate liver triglyceride accumulation was evident in the 1,000ppm group and peaked at 40mg/gm of tissue after 7 weeks of exposure. Focal hepatocyte necrosis occurred in 40% of the mice exposed to 1,000ppm for 12 weeks. This necrosis was associated with an acute inflammatory infiltrate and hypertrophy of Kupffer cells. These findings indicate that the pathological alternations observed with 1,1,1-trichloroethane are similar to those observed with dichloromethane except for different time courses of the effects and different degrees of recovery. The toxic effects of 1,1,1-trichloroethane are of a similar type to those produced by carbon tetrachloride but appear much less severe.
Mcnutt, N. S.↗
New precious metal containing normal spinels: LiRhRu 1-x Ir x O 4 , LiFeIr 1-x Ru x O 4 , and LiCoIr 1-x Ru x O 4
Large spin-orbit-coupled cations in geometrically frustrated crystal structures have the most suitable setting for exploring novel exotic states of matter. Spinel oxides (AM 2 O 4 ) are well-known examples of geometrically frustrated systems. In this study, we report for the first time the synthesis of compositions LiRhRu 1-x Ir x O 4 (x = 0–0.5), LiFeIr 1-x Ru x O 4 (x = 0–0.5), and LiCoIr 1-x Ru x O 4 (x = 0–0.3) containing precious metal cations on edge-sharing octahedral M-sites, and systematically investigate their magnetic and electrical properties. 57 Fe Mössbauer spectroscopy revealed that iron is trivalent in all LiFeIr 1-x Ru x O 4 solid solutions. Magnetic measurements indicate deviations from theoretical spin-only magnetic moment values, indicating the influence of spin-orbit coupling owing to the presence of 4d and 5d block elements. The LiFeIr 1-x Ru x O 4 series shows spin-glass-like freezing behavior with T g ≈ 20 K, and a small frustration index (f ≈ 1-2), indicating that the frustration originates from site disorder. LiRhRu 1-x Ir x O 4 and LiCoIr 1-x Ru x O 4 exhibit strongly geometrically frustrated magnetism. Electrical resistivity measurements as a function of temperature indicate that all phases are semiconducting. Seebeck coefficient measurements show that LiRhRu 1-x Ir x O 4 and LiFeIr 1-x Ru x O 4 are p-type semiconductors with holes as the major charge carriers. A sign reversal of the Seebeck coefficient indicates both holes and electrons as carriers for LiCoIr 1-x RuxO 4 (x = 0–0.2), but only holes as major carriers for x = 0.3. Here, the Seebeck coefficient and power factor increase drastically in the LiRhRu 1-x Ir x O 4 solid solution with Ir substitution, reaching a maximum of ≈ +125 μV/K and ≈2.3×10 -6 W/mK 2 at ∼650 K for x = 0.5.
Charge carriers↗
Substituted 1,1,1-Triaryl-2,2,2-Trifluoroethanes and processes for their synthesis
Synthetic procedures are described for tetraalkyls, tetraacids and dianhydrides substituted 1,1,1-triaryl-2,2,2-trifluoroethanes which comprises: (1) 1,1-bis(dialkylaryl)-1 aryl-2,2,2-trifluoroethane; (2) 1,1-bis(dicarboxyaryl)-1 aryl-2,2,2-trifluoroethane; or (3) cyclic dianhydride or diamine of 1,1-bis(dialkylaryl)-1 aryl-2,2,2,-trifluoroethanes.
Alston, William B.↗
Substituted 1,1,1-Triaryl-2,2,2-Trifluoroethanes and Processes for their Synthesis
Synthetic procedures to tetraalkyls. tetraacids and dianhydrides substituted 1,1,1-triaryl-2,2,2-trifluoroethanes which comprises: (1) 1.1-bis(dialkylaryl)-1-aryl-2,2,2 -trifluoroethane, (2) 1,1-bis(dicarboxyaryl)-1-aryl-2.2,2- trifluoroethane or (3) cyclic dianhydride or diamine of 1,1-bis(dialkylaryl)-1-aryl-2,2,2- trifluoroethanes. The synthesis of (1) is accomplished by the condensation reaction of an aryltrifluoromethyl ketone with a dialkylaryl compound. The synthesis of (2) is accomplished by oxidation of (1). The synthesis dianhydride of (3) is accomplished by the conversion of (2) to its corresponding cyclic dianhydride. The synthesis of the diamine is accomplished by the similar reaction of an aryltrifluoromethyl ketone with aniline or alkyl substituted or disubstituted anihnes. Also, other derivatives of the above are formed by nucleophilic displacement reactions.
Alston, William B.↗
Correlation of physical properties with molecular structure for dicyclic hydrocarbons : I -2-n-alkylbiphenyl, 1,1-diphenylalkane,a,w-diphenylalkane; 1,1-dicyclohexylalkane, and a,w-dicyclohexylalkane series
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FUELS - 1,1-DICYCLOHEXYLALKANES↗
Synthesis, purification and physical properties of hydrocarbons of the naphthalene series I : 1-methylnaphthalene, 1-ethylnaphthalene, 1-butylnaphthalene, and 1-isobutylnaphthalene
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1-ISOBUTYLNAPHTHALENE↗
A study of the biological effect of continuous inhalation exposure of 1, 1, 1-trichloroethene (methyl chloroform) on animals
The effects of continuous exposure to 1,1,1-trichloroethane on hepatic morphology and function are evaluated and compared with those produced by methylene chloride (dichloromethane) to determine environmental concentrations of each compound that would produce a similar biological response, i.e., a comparable increase in liver triglycerides over control levels. Experimental findings on mice, rats, dogs, and monkeys indicate that the pathological alternations observed with 1,1,1-trichloroethane are similar to those observed with dichloromethane except for different time courses of the effects and different degrees of recovery. A ten fold greater atmospheric concentration of 1,1,1-trichloroethane is required to produce the minimal liver changes found at 100 ppm dichloromethane.
Macewen, J. D.↗
Si–Cl Bond Activations at Ni(0) to Give Bimetallic Ni(I) μ 1,2 -Cl–SiR 1 R 2 Complexes that Undergo Selective Hydrogenolyses to R 1 R 2 SiH 2 Dihydrosilanes
Chlorosilanes are cheap and abundant raw materials as crucial building blocks in silicon chemistry, yet the metal-mediated activation and functionalization of Si–Cl bonds typically require precious metal sources due to their thermodynamic inertness. Herein, we report the stoichiometric, facile activation, and hydrogenolysis of chlorosilanes mediated by a series of low-valent NHC–Ni (NHC = N-heterocyclic carbene) complexes. Treatment of a Ni(0) complex (IPr)Ni(η 6 -toluene) (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazole-2-ylidene) with chlorosilanes (R 1 R 2 SiCl 2 , R 1 = Cl, R 2 = Cl, Me, Ph, or R 1 = R 2 = Me, Et, Ph, 4-MePh) rapidly afforded di-Ni(I) complexes with a bridging silyl ligand ([(IPr)Ni] 2 (μ-SiR 1 R 2 Cl)(μ-Cl), 1 R1,R2 ) in high yields. Use of a bulkier chlorosilane, Ph 2 SiCl 2 , allowed the isolation of the mono-Ni(II) silyl complex (IPr)Ni(SiPh 2 Cl)Cl (2 Ph ) as an intermediate generated via Si–Cl oxidative addition, which underwent comproportionation with (IPr)Ni(η 6 -toluene) to form 1 Ph,Ph in nearly quantitative yield. Interestingly, 1 R1,R2 was found to react with H 2 at room temperature to form mono- or di-hydrosilanes in moderate to high yields, and the product selectivity was found to be highly dependent on the identity of substituents on Si. In conclusion, these results demonstrate a novel example of facile Si–Cl activation and hydrogenolysis mediated by low-valent mono- and dinuclear NHC–Ni complexes under mild conditions.
Liu, Tianchang [University of California, Berkeley↗
Comparison of the T(sub 1) and D(sub 1) Diagnostics: A New Definition for the Open-Shell D(sub 1) Diagnostic
It is shown that the T(sub 1) operator used in a previous study to define the open-shell D(sub 1) diagnostic is invalid, and leads to an arbitrary definition of the open-shell D(sub 1) diagnostic. A new definition is proposed that eliminates this ambiguity and approximately restores the mathematical relationship previously noted between the closed-shell D(sub 1) and T(sub 1) diagnostics. Statistical comparison of the T(sub 1) and D(sub 1) diagnostics shows a very high degree of correlation between them, although it is argued that both diagnostics used together can provide more information than either can separately.
Lee, Timothy J.↗
Integral cross sections for the direct excitation of the A 3 (sigma) u +, B 3 (pi) g, W 3 (delta) u, B' 3 (sigma) u -, a' 1 (sigma) u -, a 1 (pi) g, w 1 (delta) u, and C 3 (pi) u electronic states in
Integral cross sections for electron impact excitation out of the ground state (X 1(sigma)g +) to the A 3(sigma)u +, B 3(pi)g, W 3(delta)u, B' 3(sigma)u -, a' 1(sigma)u -, a 1(pi)g, w 1(delta)u, and states in N2 are reported at incident energies ranging between 10 and 100 eV. These data have been derived by integrating differential cross sections previously reported by this group. New differential cross section measurements for the a 1(pi)g state at 200 eV are also presented to extend the range of the reported integral cross sections for this state, which is responsible for the emissions of the Lyman-Birge-Hopfield band system (a 1(pi)g (rightwards arrow) X 1(sigma)g +). The present results are compared and critically evaluated against existing cross sec In general, the present cross sections are smaller than previous results at low impact energies from threshold through the excitation function peak regions. These lower cross sections have potentially significant implications on our understanding of UV emissions in the atmospheres of Earth and Titan.
Ultraviolet Imaging Spectograph↗
Evidence of h b ( 2 P ) → ϒ ( 1 S ) η Decay and Search for h b ( 1 P , 2 P ) → ϒ ( 1 S ) π 0 with the Belle Detector
We report the first evidence for the h b ( 2 P ) → ϒ ( 1 S ) η transition with a significance of 3.5 standard deviations. The decay branching fraction is measured to be B [ h b ( 2 P ) → ϒ ( 1 S ) η ] = ( 7.1 − 3.2 + 3.7 ± 0.8 ) × 10 − 3 , which is noticeably smaller than expected. We also set upper limits on π 0 transitions of B [ h b ( 2 P ) → ϒ ( 1 S ) π 0 ] < 1.8 × 10 − 3 , and B [ h b ( 1 P ) → ϒ ( 1 S ) π 0 ] < 1.8 × 10 − 3 , at the 90% confidence level. These results are obtained with a 131.4 fb − 1 data sample collected near the ϒ ( 5 S ) resonance with the Belle detector at the KEKB asymmetric-energy e + e − collider. Published by the American Physical Society 2024
Kovalenko, E. (ORCID:0000000180841931)↗
Sputter deposition of Ta 1 W 1 Au 1 Bi 7 films for next generation hohlraums
Hohlraum simulation predicts a higher x-ray drive from Ta 1 W 1 Au 1 Bi 7 compared with our current Au hohlraum. Here, we study the effect of deposition process parameters including deposition rate, working pressure, target-to-substrate distance, substrate bias, and substrate temperature on the microstructure of Ta1W1Au1Bi7 films deposited by direct current magnetron sputtering onto planar substrates. We found that the substrate temperature has a pronounced effect on the film microstructure. This is attributed to the Bi low melting point (271°C) causing its adatom mobility to be strongly dependent on the substrate temperature. Additionally, we observed phase separation for films deposited with a high substrate bias. These results have important implications for the development of a robust Ta 1 W 1 Au 1 Bi 7 hohlraum fabrication process.
36 MATERIALS SCIENCE↗