Empirical Regularities in the Behaviour of the Critical Constants of Fluid Alkali Metals

We report new measurements of the densities of the coexisting liquid and vapour phases of the alkali metals K and Na. Comparison of the coexistence curve of K with those of Cs and Rb in reduced form shows that the alkali metals behave very similarly close to the critical temperatures. The experimental values of the critical constants T

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Ability of Naphthoquinondiazide Photoresists to Exothermic Decomposition

Occupational Safety in Industry ◽

10.24000/0409-2961-2020-10-90-96 ◽

2020 ◽

pp. 90-96

Author(s):

A.N. Shushpanov ◽

◽

A.Ya. Vasin ◽

V.M. Raykova ◽

G.G. Gadzhiev ◽

...

Keyword(s):

Convective Heat Exchange ◽

Inert Atmosphere ◽

Necessary Condition ◽

Critical Temperatures ◽

Good Convergence ◽

Measuring Devices ◽

Explosive Transformation ◽

Exothermic Decomposition ◽

Experimental Approaches ◽

Experimental Values

The article considers two intermediate products of positive photoresists (1,2-naphthoquinonediazide-(2)-5-sulfonic acid of monosodium salt — Dye M and 1,2-naphthoquinonediazide-(2)-5-sulfochloride — Dye N2) from the standpoint of the tendency to explosive transformation. The experimental values of flash points determined on the OTP setup were 130 °C for Dye M and 95 °C for Dye N2. These values are close to the temperatures of the beginning of intensive exothermic decomposition (132 and 111 °C, respectively) obtained by thermogravimetric analysis. In addition, this analysis showed the presence of exothermic peaks in the studied samples both in the air and in an inert atmosphere of helium, which is a necessary condition for the manifestation of a tendency to explosive transformation. To confirm the possibility of explosive transformation, the flash points of substances were also determined by the calculation method according to the formula, which is a consequence of the problem of thermal explosion during convective heat exchange with the environment, and gave a result close to the experimental one (the values were 138 and 105 °C, respectively). For this calculation the following was used: the kinetic parameters determined by the Kissinger method, the values of the density of substances determined on an automatic pycnometer, as well as the values of the heat of explosive transformation obtained with the help of the Real computer thermodynamic program. The research results confirming the tendency of the investigated compounds to explosive transformation, as well as the critical temperatures, exceeding which is unacceptable, were transferred to the production of FGUP GNTs NIOPIK to create a safe technological process, safe storage and transportation conditions. Considering the accuracy of the measuring devices, the process temperature should not exceed 125 °C for Dye M and 90 °C for Dye N2. The conducted studies and calculations show that the computational and experimental approaches have good convergence, give values in a close temperature range, and increase the reliability of the obtained results.

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Critical constants and density dependence of the Lorenz–Lorentz coefficient for germane

Canadian Journal of Physics ◽

10.1139/p78-150 ◽

1978 ◽

Vol 56 (9) ◽

pp. 1140-1141 ◽

Cited By ~ 2

Author(s):

P. Palffy-Muhoray ◽

D. Balzarini

Keyword(s):

Critical Temperature ◽

Density Dependence ◽

Experimental Error ◽

Critical Density ◽

Coexistence Curve ◽

Index Of Refraction ◽

Density Range ◽

Temperature Range ◽

Critical Constants

The index of refraction at 6328 Å has been measured for germane in the density range 0.15 to 0.9 g/cm3. The temperature and density ranges over which measurements are made are near the coexistence curve. The coefficient in the Lorenz–Lorentz expression, [Formula: see text], is constant to within 0.5% within experimental error for the temperature range and density range studied. The coefficient is slightly higher near the critical density. The critical density is measured to be 0.503 g/cm3. The critical temperature is measured to be 38.92 °C.

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Particle entropy and depairing in hot nuclei

International Journal of Modern Physics E ◽

10.1142/s0218301316500932 ◽

2016 ◽

Vol 25 (11) ◽

pp. 1650093 ◽

Cited By ~ 1

Author(s):

J. Dhivya Saranya ◽

N. Boomadevi ◽

T. R. Rajasekaran

Keyword(s):

Single Particle ◽

Mass Region ◽

Shell Closure ◽

Critical Temperatures ◽

Level Densities ◽

Hot Nuclei ◽

Pairing Correlations ◽

Experimental Values ◽

Low Entropy ◽

Interesting Analogy

The nuclear level densities and single particle entropies are predicted for nuclei in the mass region [Formula: see text] within a framework of statistical theory of hot nuclei method. In this method, particle-number and energy conservation as well as nuclear pairing correlations are included in the partition function of grand canonical ensemble. The suppression of pairing correlations is distinctly noticed in temperature dependence of entropies between the critical temperatures [Formula: see text] MeV and [Formula: see text] MeV for [Formula: see text], [Formula: see text] and [Formula: see text] isotopes of the elements. These structural thermodynamic entropies are interpreted as a remarkable signature of the superfluid to normal phase transition connected to the vanishing of pairing gap. The calculated level densities are compared with recent experimental values. In addition, the single particle entropy of intermediate-mass nuclei is depicted as half of the entropy of mid-shell nuclei in the rare-earth region. As a consequence, the [Formula: see text] shell closure of [Formula: see text]V carries low entropy at low excitation energy presents an interesting analogy to the [Formula: see text] shell closure of [Formula: see text]Ni. Merely, in the case of odd–even [Formula: see text] has higher entropy than the even–even [Formula: see text] nucleus.

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STUDIES ON IONIC SOLVATION: PART III. NEW THEORY FOR CALCULATING HEATS OF HYDRATION OF MONOVALENT IONS AT 25 °C

Canadian Journal of Chemistry ◽

10.1139/v60-298 ◽

1960 ◽

Vol 38 (11) ◽

pp. 2203-2216 ◽

Cited By ~ 5

Author(s):

A. M. Azzam

Keyword(s):

Alkali Metals ◽

Ionic Radius ◽

Present Theory ◽

Ionic Solvation ◽

Positive Ions ◽

Monovalent Ions ◽

Ionic Size ◽

Monovalent Ion ◽

Experimental Values ◽

Good Agreement

From Part I of this series, the structure of solution around a completely hydrated monovalent ion could be visualized. On the basis of this picture, the ionic heats of hydration is to be due to three terms. These three terms are critically discussed and evaluated for the case of alkali metals and halide ions.The present theory shows that the Born–Bjerrum term contributes a significant part to the heat and that the ionic radius value included in this term must be dependent only on the charge and not on the ionic size. The most probable value is 2.4 Å for the positive ions and 2.9 Å for the negative ions.The calculated ionic heats of hydration, which are in good agreement with the experimental values, are compared with those of previous theories.

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The critical constants and orthobaric densities of acetone, chloroform, benzene, and carbon tetrachloride

Canadian Journal of Chemistry ◽

10.1139/v69-646 ◽

1969 ◽

Vol 47 (20) ◽

pp. 3893-3898 ◽

Cited By ~ 16

Author(s):

A. N. Campbell ◽

R. M. Chatterjee

Keyword(s):

Critical Temperature ◽

Carbon Tetrachloride ◽

Log P ◽

Critical Temperatures ◽

Rectilinear Diameter ◽

The Law ◽

Specific Volumes ◽

Critical Constants

The specific volumes and pressures in the saturated states of the pure liquids acetone, benzene, chloroform, and carbon tetrachloride have been determined from a temperature of 100 °C and a pressure of about 2 atm up to the highest temperatures and pressures at which liquid and vapor coexist. The critical temperatures have been determined by the method of disappearance of meniscus, critical densities from the law of the rectilinear diameter, and critical pressures by extrapolation of the log P vs. 1/T line to the critical temperature.

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THEORETICAL ASPECTS OF THE FIELD INDUCED SUPERCONDUCTIVITY IN POLYACENES AND C60

International Journal of Modern Physics B ◽

10.1142/s0217979202011299 ◽

2002 ◽

Vol 16 (11n12) ◽

pp. 1547-1551

Author(s):

S.-L. DRECHSLER ◽

G. PAASCH ◽

J. MÁLEK ◽

S. V. SHULGA ◽

H. ESCHRIG ◽

...

Keyword(s):

Tight Binding ◽

Band Structure Calculation ◽

Full Potential ◽

Coupling Constant ◽

Phonon Coupling ◽

Critical Temperatures ◽

Binding Model ◽

Electron Phonon Coupling ◽

Strong Coulomb ◽

Experimental Values

The electronic structure and the superconductivity in field-doped polyacenes are considered. Within a modified Thomas–Fermi approach for typical experimental values of the surface charge density the injected charge is confined to a monolayer. The electron–phonon coupling constant for internal modes λintra is estimated using the work of Devos and Lanoo (Ref. 4) and the density of states N(0) estimated from a 2D tight-binding model derived from a full potential LDA band structure calculation for bulk anthracene. The empirical values of the Coulomb pseudopotentials are significantly enhanced. The strong Coulomb interaction is considered as a key quantity which determines the large differences in the critical temperatures achieved for n-doped polyacenes and C 60.

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Empirical Relations Between the Critical Constants of Fluid Alkali Metals

Physics and Chemistry of Liquids ◽

10.1080/00319108608078502 ◽

1986 ◽

Vol 16 (1) ◽

pp. 77-81 ◽

Cited By ~ 28

Author(s):

R. G. Chapman ◽

N. H. March

Keyword(s):

Alkali Metals ◽

Empirical Relations ◽

Critical Constants

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Influence of nonlocality in the spin–spin interaction functional on the Pauli susceptibility of Li, Na, and K

Canadian Journal of Physics ◽

10.1139/p81-063 ◽

1981 ◽

Vol 59 (4) ◽

pp. 500-505 ◽

Cited By ~ 7

Author(s):

A. H. MacDonald ◽

K. L. Liu ◽

S. H. Vosko ◽

L. Wilk

Keyword(s):

Spin Density ◽

Density Functional ◽

Alkali Metals ◽

Spin Exchange ◽

Local Approximation ◽

Spin Interaction ◽

Functional Formalism ◽

Exchange Correlation ◽

Experimental Values ◽

Pauli Susceptibility

Two suggested nonlocal approximations for the spin–spin exchange-correlation interaction functional of the spin-density functional formalism have been applied to the calculation of the Pauli susceptibility, χp, of the alkali metals. The nonlocal approximations were found to imply values of the density-functional Stoner parameter, I, typically ~ 3% lower than values implied by the more usual local approximation. This qualitative trend was found to be supported by comparison of available experimental values of χp with new more accurate theoretical values for the local approximation to χp.

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