scholarly journals Specific heat at constant pressure from first principles: contributions from fully anharmonic vibrations

2020 ◽  
Vol 6 (12) ◽  
pp. 125924
Author(s):  
Christopher M Stanley
Keyword(s):  
Specific Heat ◽  
First Principles ◽  
Constant Pressure ◽  
Anharmonic Vibrations

A Rational Equation of State for Water and Water Vapor in the Critical Region

1964 ◽  
Vol 86 (3) ◽  
pp. 320-326 ◽  
Author(s):  
E. S. Nowak
Keyword(s):  
Water Vapor ◽  
Equation Of State ◽  
Thermodynamic Properties ◽  
Specific Heat ◽  
Critical Point ◽  
Critical Region ◽  
Constant Pressure ◽  
Parametric Equation ◽  
Enthalpy And Entropy ◽  
Specific Volumes

A parametric equation of state was derived for water and water vapor in the critical region from experimental P-V-T data. It is valid in that part of the critical region encompassed by pressures from 3000 to 4000 psia, specific volumes from 0.0400 to 0.1100 ft3/lb, and temperatures from 698 to 752 deg F. The equation of state satisfies all of the known conditions at the critical point. It also satisfies the conditions along certain of the boundaries which probably separate “supercritical liquid” from “supercritical vapor.” The equation of state, though quite simple in form, is probably superior to any equation heretofore derived for water and water vapor in the critical region. Specifically, the deviations between the measured and computed values of pressure in the large majority of the cases were within three parts in one thousand. This coincides approximately with the overall uncertainty in P-V-T measurements. In view of these factors, the author recommends that the equation be used to derive values for such thermodynamic properties as specific heat at constant pressure, enthalpy, and entropy in the critical region.

4. On the Mechanical Action of Heat. Note as to the Dynamical Equivalent of Temperature in Liquid Water, and the Specific Heat of Atmospheric Air and Steam.

1857 ◽  
Vol 3 ◽  
pp. 5-8
Author(s):  
W. J. Macquorn Rankine
Keyword(s):  
Specific Heat ◽  
Liquid Water ◽  
Constant Pressure ◽  
Mechanical Action ◽  
Atmospheric Air ◽  
Apparent Specific Heat

In the author's paper on the Mechanical Action of Heat (Trans. Roy. Soc. Edin., Vol. XX., Part I), the calculations depending on the dynamical equivalent of temperature in liquid water were founded on the experiments of De la Roche and Bérard on the ratio of the apparent specific heat of atmospheric air under constant pressure to that of water. The equivalent thus obtained was about one-tenth part less than Mr Joule's. Since then, the author, having become acquainted with the details of Mr Joule's experiments, has come to the conclusion that Mr Joule's equivalent is correct to aboutof its amount, and that the discrepancy in question originates chiefly in the experiments of De la Roche and Bérard.

Specific Heat Capacity at Constant Pressure of Ethanol by Flow Calorimetry

2012 ◽  
Vol 57 (6) ◽  
pp. 1700-1707 ◽  
Author(s):  
Taishi Miyazawa ◽  
Satoshi Kondo ◽  
Takuya Suzuki ◽  
Haruki Sato
Keyword(s):  
Heat Capacity ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Constant Pressure ◽  
Flow Calorimetry

scholarly journals First-principles study on the electrical and thermal properties of the semiconducting Sc3(CN)F2 MXene

RSC Advances ◽  
2018 ◽  
Vol 8 (40) ◽  
pp. 22452-22459 ◽  
Author(s):  
Kan Luo ◽  
Xian-Hu Zha ◽  
Yuhong Zhou ◽  
Zhansheng Guo ◽  
Cheng-Te Lin ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Thermal Properties ◽  
Dft Calculations ◽  
Specific Heat ◽  
Thermal Expansion Coefficient ◽  
First Principles ◽  
Two Dimensional ◽  
Nanoelectronic Devices ◽  
Low Thermal Expansion ◽  
High Carrier

The two-dimensional semiconducting Sc3(CN)F2 MXene presents relatively high carrier mobilities, specific heat and low thermal expansion coefficient from DFT calculations, and produces a good application prospect for nanoelectronic devices.

scholarly journals VIII.—Note as to the Dynamical Equivalent of Temperature in Liquid Water, and the Specific Heat of Atmospheric Air and Steam, being a Supplement to a Paper On the Mechanical Action of Heat

1853 ◽  
Vol 20 (2) ◽  
pp. 191-193
Author(s):  
William John Macquorn Rankine
Keyword(s):  
Cast Iron ◽  
Specific Heat ◽  
Liquid Water ◽  
Royal Society ◽  
Constant Pressure ◽  
Mechanical Action ◽  
Numerical Results ◽  
Detailed Account ◽  
Atmospheric Air ◽  
Apparent Specific Heat

(33*.) In my paper on the Mechanical Action of Heat, published in the 1st Part of the 20th Volume of the Transactions of the Royal Society of Edinburgh, some of the numerical results depend upon the dynamical equivalent of a degree of temperature in liquid water. The value of that quantity which I then used, was calculated from the experiments of De la Roche and Bérard on the apparent specific heat of atmospheric air under constant pressure, as compared with liquid water.The experiments of Mr Joule on the production of heat by friction, give, for the specific heat of liquid water, an equivalent about one-ninth part greater than that which is determined from those of De la Roche and Bérard. I was formerly disposed to ascribe this discrepancy in a great measure to the smallness of the differences of temperature measured by Mr Joule, and to unknown causes of loss of power in his apparatus, such as the production of sound and of electricity; but, subsequently to the publication of my paper, I have seen the detailed account of Mr Joule's last experiments in the Philosophical Transactions for 1850, which has convinced me, that the uncertainty arising from the smallness of the elevations of temperature, is removed by the multitude of experiments (being forty on water, fifty on mercury, and twenty on cast iron); that the agreement amongst the results from substances so different, shews that the error by unknown losses of power is insensible, or nearly so; and that the necessary conclusion is, that the dynamical value assigned by Mr Joule to the specific heat of liquid water, viz.:—772 feet per degree of Fahrenheit, does not err by more than two or at the utmost, three feet; and therefore, that the discrepancy originates chiefly in the experiments of De la Roche and Bérard.

Solid molecular phases of Hydrogen via constant-pressure first-principles Molecular Dynamics

1997 ◽  
Vol 499 ◽  
Author(s):  
Jorge Kohanoff ◽  
Sandro Scandolo
Keyword(s):  
Molecular Dynamics ◽  
First Principles ◽  
Degrees Of Freedom ◽  
Constant Pressure ◽  
Phase Iii ◽  
Orthorhombic Structure ◽  
Lattice Constants ◽  
Symmetry Phase ◽  
Dynamics Simulations ◽  
Zone Sampling

ABSTRACTBy performing constant pressure ab initio molecular dynamics simulations we analyse the high pressure phases of molecular solid hydrogen. We use a gradient corrected LDA, and a freshly implemented efficient technique for Brillouin zone sampling. An extremely good k-point sampling turns out to be crucial for obtaining the correct ground state. Our constant pressure approach allows us to optimize simultaneously the ori-entational degrees of freedom, the lattice constants, and the space group. This can be done either by a local optimization tehcnique, or by running molecular dynamics (MD) trajectories. The MD allows for the system to undergo structural transformations spontaneously. In the lower pressure, namely for the broken symmetry phase (BSP or phase II), we find a quadrupolar orthorhombic structure, of Pca21 symmetry. By means of an MD investigation, we find, at higher pressures, a slightly distorted orthorhombic structure of Cmc21 symmetry. This structure cannot be straightforwardly identified with the H-A phase (or phase III) because: 1) it is metallic, and 2) the Raman vibron discontinuity would be far too large compared to experiment. In fact, we argue that this phase is the first metallic molecular phase of hydrogen. Metallization would happen then, not via a band-overlap mechanism, but due to a structural transformation. By comparing total enthalpies, we also give suggestions for the structure of phase III.

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