synonymPhase state(Phase state) generally refers to the state of matter (material state)
State of matter, scientific nameAggregate stateIt refers to the relatively stable state of general substances under certain temperature and pressure, usually referring to solid, liquid and gas states.The above three states of matter can be transformed into each other.For example, water (liquid) will form ice (solid) when it is cold, and will become steam (gaseous) when it is heated to a higher temperature.
State of matter (state of matter) refers to the appearance of different phases of a substance.In the early days, the state of matter was distinguished by its volume property.In the solid state, the substance has a fixed shape and capacity;In the liquid state, the material maintains a fixed capacity but its shape will change with the shape of the container;In the gaseous state, matter will expand to diffuse whether it has capacity or not.Scientists classify molecules according to their interrelationships.Solid state means that molecules will only vibrate at a fixed position due to mutual attraction.In liquid, the distance between molecules is still relatively close, and there is still some attraction between molecules, so they can only move in a limited range.As for the gas state, the distance between the molecules is far, so the attraction between the molecules is not significant, so the molecules can move at will.Plasma state（Plasma）Is a highly ionized gas that occurs at high temperatures.Because the mutual attraction isIonic forceTherefore, the plasma state is considered as the fourth state of matter, which is a universal state of matter aggregation in the universe.If a state of matter is not composed of molecules but of different forces, a new state of matter will be formed.For example:Quark gluon plasmaEtc.
The state of matter (state of matter) can also be expressed by phase transformation.Phase transformation can be structural transformation or some unique properties.According to this definition, each phase can be separated from other phases through phase transformation.For example, water is the phase of several solids.SuperconductivityIt is extended from the phase transformation, so there is a state of superconductivity.Similarly, the liquid crystal state is divided by the phase transition and has different properties at the same time.
Basic state
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solid state
Particles (including ions, atoms or molecules) areTight arrangement。There is a strong attraction between particles, so they can only vibrate in situ.Therefore, the solid has the characteristics of stability, fixed shape and fixed capacity, and its shape can only be changed when it is cut or broken by force.In crystalline solids, particles (including atoms, molecules, and ions) arethree-dimensional spaceThe same substance can be arranged in different formscrystal structure。For example, iron is face centered cubic at 912 ℃, and body centered cubic is between 912 ℃ and 1394 ℃.Another example is ice. There are 15 kinds of crystal structures of ice known in the world. These 15 kinds of solid material states exist under different temperatures and pressures.In the process of changing the state of matter, solids will melt into liquids, while liquids will solidify into solids.If the solid is directly transformed into gas, for exampleatmospheric pressureCO undertwo, which is called sublimation, and the opposite is sublimation.
Strictly speaking, the physical solid state should refer to the "crystalline state", that is, the state of various crystals.The most common crystal is table salt, which is composed of many cubic crystals.There are also many regular crystals with different colors and shapes.The prominent feature of a substance in solid state is that it has a certain volume andgeometry，physical propertyhaveanisotropy。There is a certain melting point, and the temperature does not change when melting.
In solids, molecules or atoms are arranged regularly.Each molecule or atom vibrates in its own fixed position.This structure of crystal is calledSpatial latticeStructure.
liquid state
When temperature and pressure are constant, the capacity of liquid is fixed.When a solid is heated above its melting point, it becomes a liquid.The force between internal molecules (internal atoms or internal ions) cannot be ignored, but the molecules have enough energy, so they can have relative motion, and the structure is also fluid.The shape of the liquid is uncertain, and is determined by the shape of the container.Generally, the capacity of liquid is larger than that of solid,water（HtwoO) Is aCounterexampleBecause the density of water rises from 0 ℃ to 4 ℃ and reaches the peak.The substance exists in liquidmaximum temperatureAnd maximum pressurecritical temperatureandcritical pressure。
Liquid has fluidity. Unlike solid, liquid hasIsotropyFeatures (in different directionsphysical propertyThe same), because when an object changes from a solid to a liquid, the molecules or atoms move violently due to the rise of temperature, and it is impossible to keep the original fixed position, so flow occurs.At this time, the attraction between molecules or atoms is relatively large, so that they do not disperse far away, so the liquid has a certain volume.In a small area inside the liquid, there is still a crystal like structure - "crystal like zone".Liquidity is formed by the movement of "crystal like regions" between each other.
Gaseous
In the gaseous state, the molecules have enough kinetic energy toMolecular forceThe impact ofideal gasIs 0), and the distance between molecules is also far.Gas has no limited shape and capacity, but it will occupy the entire sealed container.Liquid can be transformed into gas by heating to boiling point under normal pressure or pressurizing under normal temperature.WhenGas temperatureWhen the temperature is lower than the critical temperature, this gas is called vapor and can be changed into liquid by pressurization alone.If the pressure of gas is equal to that of liquidVapor pressureThe two can reach equilibrium, and so can the solid.When the temperature and pressure of a gas exceed their owncritical pressureAnd critical temperatureSupercritical fluidIt has the characteristics of gas and is a high density solvent, so it has many uses in industry.E.g. supercriticalcarbon dioxideAvailable throughSuperfluidExtraction method to extractcaffeineTo produce decaffeinated coffee.
When heated, a liquid will change into a gas.At this time, molecules or atoms move more violently, and the "crystal like zone" no longer exists.As the distance between molecules or atoms increases, the gravity between them can be ignored, so the gas state is mainly represented by the irregular movement of molecules or atoms, resulting in the fluidity of gas characteristics, no fixed shape and volume, and easy compression;Physical properties haveIsotropy。
Liquid crystals have the characteristics of liquid fluidity and orderly arrangement of solids.Molecules have the fluidity of liquid, but they can only point in the same direction (within a certain range), and can not twist freely.Some liquid crystals have great uses in science and technology, such asLiquid crystal display。
Liquid crystals are sensitive to small changes in external factors (such as heat, electricity, light, pressure, etc.).It is these characteristics that make it widely used in many aspects.Liquid crystal belongs toOrganic compoundUp to now, there have been more than 5000 synthetic liquid crystals.
Amorphous body
Amorphous body(also known as non lens) has an irregular structure like a liquid, but because the movement between molecules is relatively not free, it is usually included in the category of solid.Common examples are glasspolystyrene、synthetic rubberOr other polymers.Many amorphous objects are heated toGlass transition temperatureWill soften into liquid.At this time, the molecule isfree flow Of.There is no long distance and orderly arrangement of amorphous objects, but within a limited range,Oxygen atom(O) WithRegular tetrahedronArrange and surroundsilicon(Si) atom.Some liquids belong toNon Newtonian fluid, the viscosity is affected byForceandShear stressImpact.Therefore, under a certain flow condition, it will become an amorphous body.
Amorphous stateAlso called amorphous orGlassy stateIs a large class of rigid solids.Highly utilizedCooling rate, develop the traditional glass process to metals and alloys, and make correspondingAmorphous material, calledMetallic glassorGlassy metal。There are many kinds of amorphous materials,Silica（SiOtwo）, as well as silica and Al, NaMg、CaThe mixture of oxides of other elements constitutes the oldest and most importantInorganic glassIn the past 20 years, amorphous materials have been developed rapidly due to their excellent physical and chemical properties and extensive technical applications[3]。
Glassy stateAlso calledChalcopyrite。atomormoleculeUnlike the solid state, which is arranged according to a certain rule in the crystal, the atomic arrangement is only local and partialregularity（Short-range order）Without large-scale and periodic regularity（Long-range order）The solid state of.The transformation between crystal and liquid is a phase transition, and it is a first-order phase transition.stayAmorphousThere is no definitetransition temperatureWhen the temperature drops, the liquid first becomesViscosityBigger and BiggerSupercooled liquidAnd then turn into amorphous (glassy solid) at the glassy transition temperature.The glass transition temperature has no fixed value. It changes with the cooling rate of the liquid. The faster the cooling rate, the lower the glass transition temperature.The transition between supercooled liquid and amorphous is very complicated and cannot be simply regarded as phase transition[13]。Solids in this state can only crystallize after a very long time.When glass is formed from melt cooling or other methods, the internal energy contained in the system is not at the lowest value.The internal energy of a substance changes with temperature during cooling.So fromthermodynamicsViews,Glassy stateIt is in a thermodynamic unstable state. Compared with the corresponding crystalline state, it has a higher internal energy and has a tendency to transform into a crystal.However, from the kinetic point of view, it is stable, because at room temperature, due to the high viscosity of glass, it can not be spontaneously transformed into crystalline state, and it must overcome theactivation energyOnly then.So the glassy state belongs toMetastable state[14]。
for exampleOrdinary glassNot in solid state (crystalline state), butAmorphous state。Glass has no fixed melting point, and its physical properties are alsoIsotropyOf.No glass internal structureSpatial lattice, similar to the structure of liquid."ClassCrystal region”They cannot move with each other, so the glass has no fluidity.Strictly speaking, the amorphous state does not belong to the solid, because the solid refers specifically to the crystal.Amorphous state is another state of matter.In addition to ordinary glass, the common amorphous states arerubber、paraffin wax、Natural resin、asphaltAnd polymer plastics, etc.
The phenomenon that the resistance of superconductor completely disappears is calledSuperconductivity, this state is calledSuperconductive state。Superconductors have begun to enter the practical stage in some scientific and technological fields.yesHigh temperature superconductivityThe understanding of the mechanism may lead to the understanding of many so-called electronsStrong correlationUnderstanding of the physical nature of a large class of materials, and making a leap in both science and technology[4]。
DiscoveredSuperconductive materialMainly some metals, alloys and compounds, which have reached thousands.
Superfluid
When approachingAbsolute zeroSome liquids will change into another liquid state calledSuperfluid, which is characterized by zero viscosity (infinite liquidity),SuperfluidityIs its most characteristic basic property.Scientists discovered in 1937 that helium was cooled to less thanλSuperfluid is formed at temperature (2.17K).At this time, helium can flow continuously in the container and resistGeocentric suction。Helium-4In order to find your own position, you will flow slowly on the container. After a short time, the level of the two containers will be the same.The inner wall of the large container will be covered by the "Rollin membrane". If the container is not sealed, the liquid will flow out.A superfluid has an infiniteThermal conductivity, so it cannot be formed in superfluidtemperature gradient。These characteristics can be used in the superFluid stateTransfer toBose Einstein condensateTo explain.FermiCondensed matterThe superfluid ofisotopehelium-3 Or the isotope of lithium, lithium-6, is transformed at a lower temperature.
Helium-4Atoms areBoson，Bose Einstein statisticsAllow many atoms to be in onequantum stateOn.When the temperature drops toλBelow point, there is macro quantityHelium atomAt the same time, it condenses on a single quantum state with zero momentumwave functionTo describe.Temperature atλBelow pointSuperfluidityAnd other special phenomena can be explained by the characteristics of this macroscopic wave function[5]。
Bose Einstein condensate
By Einstein andBoseIt was predicted in 1924, also known as the fifth state of matter.For many years, Bose Einstein condensate has been a theoretical prediction in the gas state.Finally, the team led by Kotler, Cornell and Weiman first produced Bose Einstein condensation through experiments in 1995.Bose Einstein condensate is colder than solid state.When atoms have very close or consistent quantum levels and temperatures are very closeAbsolute zeroBose Einstein condensate will appear at (- 273 ℃).
For complianceBose Einstein statisticsAnd totalNumber of particlesConservativeideal gas, there is a very low but non-zerotransition temperatureTc, when the temperature is belowTcWhen the number of particles is limitedpercentageThe (macro quantity) part of will be aggregated to the lowest single particleEnergy statePhenomenon on the.In 1925, Einstein put SBoseProposed treatmentBlackbody radiation(Photonic gas) method is extended toPhysical particleThe theoretical prediction of ideal gas.It was later called Bose Einstein condensation.The collection of all particles gathered in the lowest energy state is called Bose Einstein condensate.
RydbergState is one of the metastable states of the powerful non ideal plasma.When the electron is highexcited stateIt is formed by post condensation.When a certain temperature is reached, these atoms will become ions and electrons.In April 2009, researchers from Stuttgart University successfullyRydberg atomAnd a ground state atom to create the Rydberg molecule (extremely cold rubidium atom is used in the experiment), and this confirmed that Chris, a physicist at the University of Colorado Boulder campusGreenHe believes that this state of matter really exists.
When the temperature reachesCelsiusIt will form at thousands of degreesplasma(ionized gas).Some plasmas are made from charged air particles and can be used in some stars such asIn the sunIt is generated when finding or lightning.When the gas is heated, the electrons will successfully escape because they have enough kinetic energyNucleusThe suction offree electron, not surrounded by atoms or molecules.Ions areChemical speciesOne of the reasons is that the number of protons is different from that of electrons and carries electric charges.Free chargeMake plasma haveConductivity, which makes it have a strong response to the magnetic field.Under extremely high temperatures, such as in stars, it is basically assumed that electrons move freely, and the extremely high-energy plasma is like an empty atomic nucleus in the electron sea.Plasma phase is the most common state of matter in the universe.Plasma can be considered as highly ionized particles, but it has completely different characteristics because of the strong ionic attraction between particles.So it is considered as a different phase orMaterial form。
Plasma is composed ofcharged particleandNeutral particleComposed ofElectromagnetic forceUnder the action, the movement and behavior of particlesCollective effectThe main system.The collective effect of plasma refers to the effect of electromagnetic forcemotion state It depends not only on the local conditions near the particle, but also on the state of other areas far away from the particle.Plasma state is another state of existence of substance different from solid state, liquid state and gas state, which is often called the fourth state of substance.Plasma appears widely in the vast universe.On the earth's surface, lightning, aurora, etc. are natural on the earthPlasmaThe radiation phenomenon of.In addition, plasma can only be generated artificially, such as gas filled electronic tubesFluorescent lamp, neon light, arcgas discharge Composed of electrons, ions and neutral particlesIonized gasIt is plasma, which is generallyElectroneutrality。Plasma has a wide range ofTechnology application, such asspace technologyControlled heatnuclear fusion、Isotope separation、radio communicationetc.[8]。
Quark gluon plasma
fromEuropean Organization for Nuclear Research(short forCERN）It was discovered in 2000.Because both protons and neutrons arequarkQuarks can be released through this state of matter and can be observed independently.Scientists can observe the properties of quarks through this state of matter, which is a great leap from theory to practice.
Quark gluon plasma is composed of many quarks, anti quarks andGluonConstituentMultibody system。It is called quark matter for short.be-allStrong interactionParticles arehadronThey are all composed of quarks, antiquarks and gluons.So far, whether in nature or throughExperimental meansNeither quark nor gluon can be found.However, strongly interactingGauge field theoryPrediction, beyond a certain thresholdenergy density (Approx. 10twenty-fourElectron volt/Metersthree）Quark, anti quark andGluonIt may break through the confinement of a single hadron pocket and move freely in a much larger space, forming a quark gluon plasma[9]。
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Degenerate matter
Under extremely high pressure, materials at normal temperature will change into a series of strange material states, collectively calledDegenerate matter 。This has aroused the interest of astrophysicists.Because they believe that in the stars, whennuclear fusionThis occurs when the "fuel" of is exhausted, for exampleWhite dwarfandneutron star。
A neutron star consisting mainly of degenerate neutronsCompact celestial body。Shortly after the discovery of neutrons in 1932, L. Landau proposed that there might beCompact star。1939 JOppenheimerAnd G. Volkov established the model of the first neutron star through calculation.High qualityStar depletion insidenuclear fuelAfter that, the star core collapsesfree electronWill be forced toNucleusThe protons in form neutrons.The gravity of the neutron star pushes most of the free electrons into the nucleus, forcing them to combine with the proton to form neutrons.The density of neutron star is extremely high, spoonfulneutron starThe material weighs 1 billion tons, and its mass is 1.7 × 10－24Gram, "radius" is 10－13The density of a single neutron in centimeter is similar.Neutron stars have extremely highNuclear densityAnd very stronggravitational field[10]。
Supersolids
SupersolidsIt can be orderly arranged in the designated space (i.e. solid or crystal), but it hasSuperfluidAnd many other non solid properties, so it is incorporated into a new material state.
Supersolids are also calledSuperstructures（Superlattice）, YesOrdered solid solutionGeneral term for structure.WhenSolid solutionAfter ordering,Unit cellEach seat in becomes different, differentConstituentThe atoms of C have priority to occupy specific seats respectively.When complete order is realizedstructure type Sometimes even the lattice type changes.After complete ordering, the lattice type also changes to simple cubic type, but it is still customarily called solid solution with superstructures[11]。
String-net liquid
In the normal solid state, the atoms in the matter should be arranged in a network, so for any electron, the spin direction of its adjacent electrons should be opposite to its own.But in the liquid state of the string like net, the atoms will be arranged in some form so that some of the adjacent electronsSpin directionIt has the same direction as it does, so it has some unique properties.Interestingly, these characteristics help explain some of theSingular phenomenonto be helpful to.
Chord shaped net liquid is also calledLiquid sublattice。It can be considered thatFast ionic conductorThe lattice of is composed of twoSublatticeOne is a rigid sublattice composed of immobile ions, and the other is a sublattice composed of movable ions.The rigid sublattice provides many positions of approximately equal energy for the movable ions, and the movable ions are randomly distributed in these positions, so it is called the liquid sublattice.The existence of liquid sublattice has been confirmed experimentally.Fast ionic conductor has the characteristics of both solid and liquid[12]。
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Note: Some experiments are very dangerous, which is not written here.
