Questions tagged [phase-diagram]

The tag has no usage guidance.

Filter by
Sorted by
Tagged with
7 votes
1 answer
168 views

Why is $H = J \sum_i (S^x_i S^x_{i+1} + S^y_iS^y_{i+1})$ always gapless for any spin $S$?

In the following I have in mind antiferromagnetic spin chains in periodic boundary conditions on a chain of even length $L$. Consider the spin-$S$ spin chain $$H = J \sum_{i=1}^L (S^x_i S^x_{i+1} + S^...
user196574's user avatar
  • 2,040
0 votes
1 answer
37 views

How do I calculate predicted curves (or surfaces) on a substance's $p$-$T$ (or $p$-$V$-$T$) phase diagram?

I just saw the announcement "Breakthrough in melting point prediction: over 100-year-old physics problem solved by Queen Mary Professor", which says that Professor Trachenko ... ...
Lawton's user avatar
  • 327
1 vote
1 answer
27 views

Why does the freezing point of water regress at select pressures before increasing again at even higher pressures?

This phase diagram of water shows how the phase of water is determined by the pressure and temperature. I find it easy enough to understand; as the pressure increases, the boiling point of water also ...
user267545's user avatar
0 votes
1 answer
85 views

Sublattice model for ternary system

Much like in an earlier post of mine, I'm now calculating the phase diagram of a ternary system (Ag-Al-Cu, to be specific), which has some phases modelled as sublattices (using this publication for ...
asbjos's user avatar
  • 25
0 votes
1 answer
61 views

How are states of matter determined experimentally?

Let's consider for example water. There is the classical phase diagram shown below which depicts the three states liquid, solid, and gaseous. My question is, how were the exact positions of the ...
a_guest's user avatar
  • 228
3 votes
1 answer
69 views

Is metallic hydrogen solid or liquid?

If I squeeze hydrogen superhard with 400-500GPa of pressure, it becomes metal so is that solid or liquid? I know gallium melts on my hand and it's metal.
user6760's user avatar
  • 13k
0 votes
0 answers
49 views

Refrigerated vacuum Soxhlet extraction

Say one wanted to efficiently extract a temperature sensitive and easily oxidized compound from a substance. I envision a Soxhlet apparatus filled with a very low BP solvent like diethyl ether. Rather ...
selene flemming's user avatar
0 votes
0 answers
21 views

Isotropic classical model with a different phase transition than its anisotropic quantum limit

I have often heard that the isotropic ferromagnetically-coupled 2d classical Ising model and the quantum 1d transverse field Ising model have similar phases and the same universality class of their ...
user196574's user avatar
  • 2,040
2 votes
1 answer
85 views

Coupling two Ising chains via an energy-energy interaction

Consider the transverse-field Ising model on a chain with periodic boundary conditions: $$ H = -\sum_{i=1}^{L} \sigma_{i}^z \sigma_{i+1}^z + h \sigma_{i}^x$$ There's a phase transition at $h=1$, which ...
user196574's user avatar
  • 2,040
1 vote
2 answers
89 views

Why do phase changes have to be isothermal processes?

I was wondering if someone can explain simply why phase changes are isothermal processes? I am studying hydrology and some of our material about snowmelt has to do with phase changes and in this ...
arv24_'s user avatar
  • 13
0 votes
0 answers
5 views

Is it possible to relate the usage of types silicon in a solar cell to a phase diagram of doped Silicon? (Si-P, Si-B)

With reading this post (Why do we need pure silicon for a solar cell to be efficient?) I am seeing these new concepts I never thought were in a solar cell. With bare minimum google searches I thought ...
MiST's user avatar
  • 1
6 votes
2 answers
2k views

Do liquids typically solidify under enough pressure?

Looking at the phase diagram of water, it looks like increasing pressure of a liquid at any temperature eventually produces a solid. Liquid water becomes Ice VII at some pressure over 1 GPa and 350-...
Alex I's user avatar
  • 386
1 vote
0 answers
65 views

Melting point of water [duplicate]

Wikipedia says about melting point that: The melting point of ice at 1 atmosphere of pressure is very close to 0 °C (32 °F; 273 K); this is also known as the ice point. But why it is very close and ...
Harjot Dhillon's user avatar
2 votes
1 answer
89 views

Phase diagram of the Ashkin-Teller model for unequal intraplane couplings

The 2d Ashkin-Teller model is a $\mathbb{Z}_2 \times \mathbb{Z}_2$ symmetric model consisting of two planes of Ising models on the square lattice with an interplane four-spin coupling: $$H = -\sum_{&...
user196574's user avatar
  • 2,040
0 votes
0 answers
27 views

What does reduced saturation pressure mean in acentric factor?

I'm currently learning about acentric factor and I don't understand what P_r^sat means... Is there a saturation pressure at critical point? Moreover, is the reason for setting reduced temperature as 0....
Lime nut's user avatar
5 votes
2 answers
416 views

Is the self-dual point always a critical point?

I was studying duality maps in my Advanced Stat. Mech. class and it was told that all self-dual points need not correspond to critical point. I understand that critical points are points where ...
QFTheorist's user avatar
2 votes
1 answer
75 views

Linearization of $\beta$-functions around Gaussian fixed points

I was reading section 8.4.4 of the book "Condensed Matter Field Theory" by Altland & Simons and I ended up with a very specific question that I couldn't resolve. After finding the ...
Jimeens's user avatar
  • 161
0 votes
1 answer
183 views

How long does it take to boil water?

Consider a simple experiment, such as boiling water in a pot in your kitchen, is it possible to estimate the time needed for the water to boil based on elementary properties of water ? In the physics ...
YoussefMabrouk's user avatar
5 votes
1 answer
263 views

Could someone explain this phase diagram to me?

I'm a litte confused by this diagram. What does the "Diamond + metastasble Graphite" and "Graphite + metastable Diamond" regions mean? I mean at room temperature and Pressures, ...
blademan9999's user avatar
  • 2,880
2 votes
1 answer
235 views

How does adding heat cause helium-3 to freeze? [duplicate]

According to here at 3MPa helium-3 actually goes from liquid to solid at 0.1 kelvin, this is the complete opposite of how normal materials behave, how is this possible?
blademan9999's user avatar
  • 2,880
0 votes
1 answer
50 views

Direction of propagation not being parallel of two light rays

Here we can see two scenarios where in the first one are two Ray's whose ditection of propagation are parallel and hence we can say that they are in phase which means they interfere constructively. ...
madness's user avatar
  • 1,191
4 votes
2 answers
119 views

Where can I find interpolation formulas or tabulated data for phase diagram(s)?

In order to program it, where can I find accurate representations of the water (or others - e.g.: CO2) phase diagrams, in the form of mathematical functions or in the form of interpolable tabulated ...
1 vote
1 answer
213 views

How to calculate the reference Gibbs energy?

I want to calculate the Zr-O diagram based on the data from this article. The article contains 4 tables with data for: pure elements, stoichiometric phases, phases of solutions, gases. How should I ...
Egor M.T.'s user avatar
2 votes
2 answers
140 views

Lennard-Jones vapor-liquid coexistence pressure

No analytical equation of state for the Lennard-Jones substance is known, but, as far as I know, one of the known best approximations is the Kolafa-Nezbeda equation of state (given in equations 30-32)....
Ale's user avatar
  • 293
1 vote
1 answer
146 views

Calculating phase diagram of $\rm Al$-$\rm Cu$ with sublattice models

I want to calculate the phase diagram of $\rm Al$-$\rm Cu$ "by hand" in Python. The "regular" LIQ, FCC and BCC phases are all good (using the excess Gibbs energies from COST-507), ...
asbjos's user avatar
  • 25
3 votes
1 answer
149 views

Metastability curve, two different definitions

I have now come across two different definitions for the spinodal curve which, together with the coexistence line, encloses two metastable phase regions. The first definition is from Tong on page 139. ...
Jahn Dorian's user avatar
2 votes
3 answers
229 views

Why the isotherm in the $p$-$V$ diagram is horizontal during the1st Order Liquid-Gas phase transition?

In the Statistical Mechanics book of Kerson Huang, it is written that "The isotherm in the $p$-$V$ diagram is horizontal during the phase transition, because the gas phase has a smaller density ...
Lusypher's user avatar
  • 187
2 votes
2 answers
388 views

Lower pressure lower boiling point

Is there an intuitive way for understanding why in lower pressure the boiling point is lower? Maybe some easy characteristic special case. Or should I just follow equation or experiment and memorize ...
romperextremeabuser's user avatar
1 vote
0 answers
48 views

Plotting phase diagrams

I was reading this article on Landau theory https://phys.libretexts.org/Bookshelves/Thermodynamics_and_Statistical_Mechanics/Book%3A_Thermodynamics_and_Statistical_Mechanics_(Arovas)/07%...
physics22's user avatar
1 vote
2 answers
396 views

Why does bubble formation only happens at the point when vapor pressure becomes equal to atmospheric pressure during boiling?

I am a high school student and I am very confused about what's actually happening at the microscopic scale in an ideal solution when it's boiling? Boiling as I understand at microscopic level is- ...
Shyam's user avatar
  • 29
-1 votes
1 answer
130 views

Can Solid takes the shape of its container

My Cambridge Physics Coursebook says that Solid "takes the shape of its container". It is endorsed by Cambridge for IGCSE physics. Is it right? How is this possible. It is very Clear and ...
Home User's user avatar
0 votes
1 answer
185 views

How to estimate the pressure drop due to venting?

For context, I'm writing a small simulation to predict the behavior of a pure substance within tanks, pipes, valves and so on for entertainment purposes. I have an issue to simulate venting. Here is ...
Zejj's user avatar
  • 3
1 vote
2 answers
90 views

If no amount of pressure can liquefy a gas at critical temperature, why does it liquefy at critical pressure?

I have read that at the critical temperature, no amount of pressure will liquefy a gas but according to the definition of critical pressure, a gas at its critical temperature will liquefy at a ...
JesusIsLord's user avatar
0 votes
1 answer
53 views

What might get me to the lowest temperature with liquid water?

I'd like to experiment with freeze drying food but the only equipment I own, is a vacuum pump+chamber and an old freezer I wouldn't mind drilling to run a vacuum pipe inside. However an important ...
Camion's user avatar
  • 555
4 votes
0 answers
41 views

Why is the supercritical fluid region a perfect rectangle?

The melting, sublimation and evaporation curves are all non straight lines in a (p,T) phase diagram, while the curves that divide liquid/gas regions from supercritical fluid region are perfectly ...
Redirectk's user avatar
  • 357
3 votes
0 answers
114 views

Van der Waals equation in PT coordinates

Can Van der Waals equation be meaningfully interpreted in PT plane? Are there modified versions of this equation, which would allow correctly reproducing the liquid-gas separation curve with a ...
Roger V.'s user avatar
  • 58.7k
1 vote
1 answer
103 views

Calculating phase diagram for immiscible system

I want to calculate the phase diagram for the Al-In system, which has an immiscible phase. As the solid elements don't have any mutual solubility, there is no excess Gibbs description for the solid ...
asbjos's user avatar
  • 25
8 votes
1 answer
120 views

Will interstellar helium condense to a liquid as space expands and cools?

Intergalactic space is 2.7K (https://en.wikipedia.org/wiki/Outer_space) Interstellar space is a little warmer. My understanding is that these will decrease over time. The phase diagrams of helium I ...
Alex K's user avatar
  • 488
0 votes
1 answer
476 views

Why do butane lighters have to be filled upside down?

Now, people say that the reason it is filled in a manner akin to this: is because butane is heavier than air, but why should that matter if the butane escapes the canister by getting propelled out of ...
Redox's user avatar
  • 1
2 votes
0 answers
97 views

Dependence of phase transition on scale factors

In a numerical experiment, I have obtained a phase diagram of the system under study. The phase diagram is obtained between two scaled quantities say, $P^{\prime}$ and $Q^{\prime}$ of the system. I ...
bubucodex's user avatar
  • 223
3 votes
3 answers
284 views

Are number of molecules per unit volume constant (say in water)?

I have a very basic doubt. I knew that $$ \rho = \frac{m}{V} $$ And since mass is constant so volume may decrease or increase depending upon density. But suppose I have water in a beaker and I read it ...
Shekhar Dangi's user avatar
0 votes
0 answers
74 views

What happens when the latent heat of a substance is more than the specific heat capacity of its liquid form?

i came upon a question involving mixing a given of 15 degree celcius water with a given amount of ice, they asked me about the final temperature of mixture... i solved this question by applying the ...
Shaishav Sharma's user avatar
1 vote
3 answers
145 views

Phase Equilibrium Conditions

In explaining phase equilibrium, my textbook gives an example of two phases ($\alpha$ and $\beta$) of the same species coexisting together and isolated from the rest of the world. With the total ...
Abe 's user avatar
  • 57
1 vote
0 answers
47 views

Can we always predict the ground state's phase of an unfrustrated quantum model with it's classical approximation?

Let's say, that we want to make a phase diagram of the Heisenberg XXZ model $$ H = - \left ( J \sum_{\left<i,i'\right>, i < i'} \bar{S}_i \cdot \bar{S}_{i'} + \lambda \sum_{\left<i,i'\...
brzepkowski's user avatar
2 votes
1 answer
537 views

Transverse-field Ising model in the presence of a longitudinal field - ferromagnetic phase diagram

I am wondering what is the phase diagram of the transverse-field Ising model in the presence of a longitudinal field, in particular, a one-dimensional spin-1/2 chain with ferromagnetic interactions. ...
T.O.Puel's user avatar
0 votes
2 answers
115 views

Phase difference calculation

I have the frequency of two waves $A$ and $B$ and I want to calculate the phase difference of $A$ relative to $B$ in degrees. I also have the phase difference in terms of time $t$ i.e. the time ...
Meow's user avatar
  • 1
1 vote
1 answer
101 views

What is beyond the supercritical fluid? [closed]

I always wondered what was beyond the supercritical fluid. At first, I thought there was nothing, but then I thought well there be an ultra-critical fluid. Is there even a phase beyond it?
EndoBotm's user avatar
0 votes
3 answers
1k views

Why does snow disappear without melting?

During very cold weather, snow often gradually disappear without melting.
Yitian Chen's user avatar
0 votes
1 answer
264 views

Is the pressure always the same for each phase of a two-phase system?

I am currently reading a textbook called Engineering and Chemical Thermodynamics but I am stuck in one part about the State Postulate and the Gibbs Phase Rule. The Gibbs Phase rule says that the ...
prado5083's user avatar
0 votes
1 answer
35 views

Can you go from a gas to a liquid without condensating through supercritical fluids?

If you were to take a gas like co2 and then heat it up and pressurize it in a specific way, would it theoretically be possible to turn the gas to liquid without using condensation? This would be hard ...
Smart Gamer 123's user avatar

1
2 3 4 5