61.   Structure of solids and liquids; crystallography (for surface, interface, and thin film structure, see 68)

61.10.-i   X-ray diffraction and scattering (for x-ray diffractometers, see 07.85.Jy; for x-ray studies of crystal defects, see 61.72.Dd, Ff)

61.10.Dp   Theories of diffraction and scattering 

61.10.Eq   X-ray scattering (including small-angle scattering) 

61.10.Ht   X-ray absorption spectroscopy: EXAFS, NEXAFS, XANES, etc. 

61.10.Kw   X-ray reflectometry (surfaces, interfaces, films) 

61.10.Nz   Single-crystal and powder diffraction 

61.12.-q   Neutron diffraction and scattering

61.12.Bt   Theories of diffraction and scattering 

61.12.Ex   Neutron scattering techniques (including small-angle scattering) 

61.12.Ha   Neutron reflectometry 

61.12.Ld   Single-crystal and powder diffraction 

61.14.-x   Electron diffraction and scattering (for electron diffractometers, see 07.65)

61.14.Dc   Theories of diffraction and scattering 

61.14.Hg   Low-energy electron diffraction (LEED) and reflection high-energy electron diffraction (RHEED) 

61.14.Lj  Convergent-beam electron diffraction, selected-area electron diffraction, nanodiffraction 

61.14.Nm   Electron holography 

61.14.Qp   X-ray photoelectron diffraction 

... ... ...   Microscopy of surfaces, interfaces, and thin films, see 68.37.-d
 

61.18.-j   Other methods of structure determination
 

61.18.Bn   Atom, molecule, and ion scattering 

61.18.Fs   Magnetic resonance techniques; Mössbauer spectroscopy 

61.20.-p   Structure of liquids

61.20.Gy   Theory and models of liquid structure 

61.20.Ja   Computer simulation of liquid structure 

61.20.Lc   Time-dependent properties; relaxation (for glass transitions, see 64.70.Pf)

61.20.Ne   Structure of simple liquids 

61.20.Qg   Structure of associated liquids: electrolytes, molten salts, etc. 

61.25.-f   Studies of specific liquid structures

61.25.Bi   Liquid noble gases 

61.25.Em   Molecular liquids 

61.25.Hq   Macromolecular and polymer solutions; polymer melts; swelling 

61.25.Mv   Liquid metals and alloys 

61.30.-v   Liquid crystals (for phase transitions in liquid crystals, see 64.70.Md;
                for electric, magnetic, and optical properties, see 77.84.Nh; for liquid 
                crystals as optical materials, see 42.70.Df; for liquid crystal devices, 
                see 42.79.Kt)

61.30.Cz   Molecular and microscopic models and theories of liquid crystal structure 

61.30.Dk   Continuum models and theories of liquid crystal structure

61.30.Eb   Experimental determinations of smectic, nematic, cholesteric, and other structures 

61.30.Gd   Orientational order of liquid crystals; electric and magnetic field effects on order

61.30.Hn   Surface phenomena:  alignment, anchoring, anchoring transitions, 
                       surface-induced layering, surface-induced ordering, wetting, 
                       prewetting transitions, and wetting transitions (see also section 68 Surfaces,
                       interfaces, thin films and low-dimensional structures) 

61.30.Jf   Defects in liquid crystals 

61.30.Mp   Blue phases and other defect-phases

61.30.Pq   Microconfined liquid crystals:   droplets, cylinders, randomly 
                      confined liquid crystals, polymer dispersed liquid crystals, and 
                      porous systems 

61.30.St   Lytropic phases 

61.30.Vx   Polymer liquid crystals
 

61.41.+e   Polymers, elastomers, and plastics  (see also 81.05.Lg in materials science;  for rheology of polymers, see 83; for polymer reactions and polymenization, see 82.35.-x)

61.43.-j   Disordered solids   (see also 81.05.Gc, 81.05.Kf, and 81.05.Rm in materials science)

61.43.Bn   Structural modeling: serial-addition models, computer simulation 

61.43.Dq   Amorphous semiconductors, metals, and alloys 

61.43.Er    Other amorphous solids 

61.43.Fs   Glasses 

61.43.Gt   Powders, porous materials 

61.43.Hv   Fractals; macroscopic aggregates (including diffusion-limited aggregates) 

61.44.-n   Semi-periodic solids

61.44.Br   Quasicrystals 

61.44.Fw   Incommensurate crystals 

61.46.+w Nanoscale materials: clusters, nanoparticles, nanotubes, and nanocrystals   (see also 36.40  Atomic and molecular clusters; for fabrication and characterization of nanoscale materials, see 81.07.-b in materials science) 

61.48.+c   Fullerenes and fullerene-related materials (see also 81.05.Tp in materials science)

61.50.-f   Crystalline state

61.50.Ah   Theory of crystal structure, crystal symmetry; calculations and modeling 

... ... ...      Crystal growth, see 81.10

61.50.Ks   Crystallographic aspects of phase transformations; pressure effects 
                 (see also 81.30.Hd)

61.50.Lt   Crystal binding; cohesive energy 

61.50.Nw   Crystal stoichiometry 

61.66.-f    Structure of specific crystalline solids (for surface structure, see 68.35.Bs)

61.66.Bi   Elemental solids 

61.66.Dk   Alloys 

61.66.Fn   Inorganic compounds 

61.66.Hq   Organic compounds 

... ... ...   Quantum crystals, see 67.80.Cx

61.68.+n   Crystallographic databases

61.72.-y   Defects and impurities in crystals; microstructure(for radiation induced defects, see 61.80; for defects in surfaces, interfaces and thin films, see 68.35.Dv and 68.55.Ln; see also 85.40.Ry Impurity doping, diffusion and ion implantation technology)

61.72.Bb   Theories and models of crystal defects 

61.72.Cc   Kinetics of defect formation and annealing 

61.72.Dd   Experimental determination of defects by diffraction and scattering 

61.72.Ff   Direct observation of dislocations and other defects (etch pits, decoration, 
                electron microscopy, x-ray topography, etc.)

61.72.Hh   Indirect evidence of dislocations and other defects (resistivity, slip, creep, 
                strains, internal friction, EPR, NMR, etc.) 

61.72.Ji   Point defects (vacancies, interstitials, color centers, etc.) and defect clusters 

61.72.Lk   Linear defects: dislocations, disclinations 

61.72.Mm   Grain and twin boundaries 

61.72.Nn   Stacking faults and other planar or extended defects 

61.72.Qq   Microscopic defects (voids, inclusions, etc.) 

61.72.Ss   Impurity concentration, distribution, and gradients (for impurities in 
                thin films, see 68.55.Ln; see also 66.30.Jt Diffusion of impurities)

61.72.Tt   Doping and impurity implantation in germanium and silicon 

61.72.Vv   Doping and impurity implantation in III–V and II–VI semiconductors 

61.72.Ww   Doping and impurity implantation in other materials 

61.72.Yx   Interaction between different crystal defects; gettering effect
 

61.80.-x   Physical radiation effects, radiation damage (for photochemical reactions, see 82.50.-m)

... ... ...     Radiation treatments, see 81.40.Wx

61.80.Az   Theory and models of radiation effects 

61.80.Ba   Ultraviolet, visible, and infrared radiation effects (including laser radiation) 

61.80.Cb   X-ray effects 

61.80.Ed    Gamma-ray effects 

61.80.Fe   Electrons and positron radiation effects 

61.80.Hg   Neutron radiation effects 

61.80.Jh   Ion radiation effects (for ion implantation, see 61.72.Tt , Vv, Ww)

61.80.Lj   Atom and molecule irradiation effects 

... ... ...     Channeling, blocking, and energy loss of particles, see 61.85+p

61.82.-d   Radiation effects on specific materials

61.82.Bg   Metals and alloys 

61.82.Fk   Semiconductors 

61.82.Ms   Insulators 

61.82.Pv   Polymers, organic compounds 

61.82.Rx   Nanocrystalline materials

61.85.+p   Channeling phenomena (blocking, energy loss, etc.)

61.90.+d   Other topics in structure of solids and liquids (restricted to
                 new topics in section 61)

62.   Mechanical and acoustical properties of condensed matter (for nonlinear acoustics of solids, see 43.25.Dc in acoustics appendix; for mechanical and acoustical  properties of interfaces and thin films, see 68.35.Gy, 68.35.Iv, and 68.60.Bs; for mechanical properties related to treatment conditions, see 81.40.Jj, Lm, Np in material science; for mechanical properties of rocks and minerals, see 91.60)

62.10.+s   Mechanical properties of liquids (for viscosity of liquids, see 66.20)

62.20.-x   Mechanical properties of solids

62.20.Dc   Elasticity, elastic constants 

62.20.Fe   Deformation and plasticity (including yield, ductility, and superplasticity) (see also 83.50.-v Deformation and flow in rheology) 

62.20.Hg   Creep 

62.20.Mk   Fatigue, brittleness, fracture, and cracks 

62.20.Qp   Tribology and hardness (see also 46.55.+d in continuum mechanics of solids)

62.25.+g   Mechanical properties of nanoscale materials

62.30.+d   Mechanical and elastic waves; vibrations(see also 43.40 Structural acoustics and vibration; 46.40  in continuum mechanics of solids)

62.40.+i   Anelasticity, internal friction, stress relaxation, and mechanical resonances (see also 81.40.Jj Elasticity and anelasticity)

... ... ...     Thermomechanical effects, see 65.40.De

... ... ...     Magnetomechanical effects, see 75.80.+q

... ... ...      Piezoelectric effects, see 77.65.-j

... ... ...     Elastooptical effects, see 78.20.Hp

62.50.+p   High-pressure and shock-wave effects in solids and liquids (for high pressure apparatus and techniques, see 07.35;  for shock-wave initiated high-pressure chemistry, see 82.40.Fp) 

62.60.+v   Acoustical properties of liquids (see also 43.35 in acoustics appendix)

... ... ...     Lattice dynamics, phonons, see 63

... ... ...     Second sound in quantum fluids, see 67.40.Pm

62.65.+k   Acoustical properties of solids

... ... ...     Magnetoacoustic effects, see 72.55.+s  and 73.50.Rb

... ... ...     Acoustoelectric effects, see 72.50.+b, 73.50.Rb, and 77.65.Dq

... ... ...     Acoustooptical effects, see 78.20.Hp

62.80.+f   Ultrasonic relaxation (see also 43.35.Fj Ultrasonic relaxation processes in liquids and solids in acoustics appendix; for ultrasonic attenuation in superconductors, see 74.25.Ld)

62.90.+k   Other topics in mechanical and acoustical properties of condensed matter (restricted to new topics in section 62)

 63.   Lattice dynamics (see also 78.30 Infrared and Raman spectra; for surface and interface vibrations, see 68.35.Ja; for adsorbate vibrations, see 68.43.Pq) 

63.10.+a   General theory

63.20.-e    Phonons in crystal lattices (for phonons in superconductors, see 74.25.Kc; see also 43.35.Gk Phonons in crystal lattice, quantum acoustics in acoustics appendix)

63.20.Dj   Phonon states and bands, normal modes, and phonon dispersion 

63.20.Kr   Phonon–electron and phonon–phonon interactions 

63.20.Ls   Phonon interactions with other quasiparticles 

63.20.Mt   Phonon–defect interactions 

63.20.Pw   Localized modes 

63.20.Ry   Anharmonic lattice modes 

63.22.+m   Phonons or vibrational states in low-dimensional 
                         structures and nanoscale materials 

63.50.+x   Vibrational states in disordered systems

63.70.+h   Statistical mechanics of lattice vibrations and displacive phase transitions

63.90.+t   Other topics in lattice dynamics (restricted to new topics in section 63)

64.   Equations of state, phase equilibria, and phase transitions(see also 82.60.-s Chemical thermodynamics)

64.10.+h   General theory of equations of state and phase equilibria (see also 05.70.Ce Thermodynamic functions and equations of state)

64.30.+t   Equations of state of specific substances

64.60.-i   General studies of phase transitions (see also 63.70 Statistical mechanics of lattice vibrations and displacive phase transitions; for critical phenomena in solid surfaces and interfaces, and in magnetism, see 68.35.Rh, and 75.40.-s, respectively)

64.60.Ak   Renormalization-group, fractal, and percolation studies of phase transitions (see also 61.43.Hv Fractals; macroscopic aggregates)

64.60.Cn   Order–disorder transformations; statistical mechanics of model systems 

64.60.Fr   Equilibrium properties near critical points, critical exponents 

64.60.Ht   Dynamic critical phenomena 

64.60.Kw   Multicritical points 

64.60.My   Metastable phases 

64.60.Qb   Nucleation (see also 82.60.Nh Thermodynamics of nucleation in physical chemistry and chemical physics) 

64.70.-p   Specific phase transitions

64.70.Dv   Solid–liquid transitions 

64.70.Fx   Liquid–vapor transitions 

64.70.Hz   Solid–vapor transitions 

64.70.Ja   Liquid–liquid transitions 

64.70.Kb   Solid–solid transitions (see also 61.50.Ks Crystallographic aspects of phase transformations, pressure effects; 75.30.Kz and 77.80.Bh for magnetic and ferroelectric transitions, respectively; for material science aspects, see 81.30.-t)

64.70.Md   Transitions in liquid crystals

64.70.Nd   Structural transitions in nanoscale materials

64.70.Pf   Glass transitions 

64.70.Rh   Commensurate–incommensurate transitions 

64.75.+g   Solubility, segregation, and mixing; phase separation(see also 82.60.Lf Thermodynamics of solutions)

64.90.+b   Other topics in equations of state, phase equilibria, and phase transitions (restricted to new topics in section 64)

65.   Thermal properties of condensed matter (see also 05.70 Thermodynamics and 44Heat transfer; for thermodynamic properties of quantum fluids and solids, see 67; for thermal properties of thin films, see 68.60.Dv; for nonelectronic thermal conduction, see 66.60, 66.70; for thermal properties of rocks and minerals, see 91.60.Ki)

65.20.+w   Thermal properties of liquids: heat capacity, thermal expansion, etc. 

65.40.-b   Thermal properties of crystalline solids (for specific heat of superconductors, see 74.25.Bt;  for specific heat of magnetic systems, see 75.40.Cx)

65.40.Ba  Heat capacity

65.40.De  Thermal expansion; thermomechanical effects

65.40.Gr  Entropy and other thermodynamical quantities

65.60.+a   Thermal properties of amorphous solids and glasses: heat capacity, thermal expansion, etc.

65.80.+n   Thermal properties of small particles, nanocrystals, nanotubes (see also 82.60.Qr Thermodynamics of nanoparticles in physical chemistry and chemical physics)

65.90.+i   Other topics in thermal properties of condensed matter (restricted 
                 to new topics in section 65)

66.   Transport properties of condensed matter (nonelectronic)

66.10.-x   Diffusion and ionic conduction in liquids

66.10.Cb   Diffusion and thermal diffusion (for osmosis, see also 82.39.Wj)

66.10.Ed   Ionic conduction 

66.20.+d   Viscosity of liquids; diffusive momentum transport

66.30.-h   Diffusion in solids (for surface and interface diffusion, see 68.35.Fx)

66.30.Dn    Theory of diffusion and ionic conduction in solids 

66.30.Fq   Self-diffusion in metals, semimetals, and alloys 

66.30.Hs   Self-diffusion and ionic conduction in nonmetals 

66.30.Jt   Diffusion of impurities 

66.30.Lw   Diffusion of other defects 

66.30.Ny   Chemical interdiffusion; diffusion barriers 

66.30.Pa   Diffusion in nanoscale solids

66.30.Qa   Electromigration 

66.30.Xj   Thermal diffusivity

66.35.+a   Quantum tunneling of defects

66.60.+a   Thermal conduction in nonmetallic liquids (for thermal conduction in liquid metals, see 72.15.Cz)

66.70.+f   Nonelectronic thermal conduction and heat-pulse propagation in solids; thermal waves (for thermal conduction in metals and alloys, see 72.15.Cz and 72.15.Eb)

66.90.+r   Other topics in nonelectronic transport properties of condensed matter (restricted to new topics in section 66)

67.   Quantum fluids and solids; liquid and solid helium(see also 05.30 Quantum statistical mechanics)

67.20.+k   Quantum effects on the structure and dynamics of nondegenerate fluids (e.g., normal phase liquid ⁴He)

67.40.-w   Boson degeneracy and superfluidity of ⁴He

67.40.Bz   Phenomenology and two-fluid models 

67.40.Db   Quantum statistical theory; ground state, elementary excitations 

67.40.Fd   Dynamics of relaxation phenomena

67.40.Hf   Hydrodynamics in specific geometries, flow in narrow channels 

67.40.Jg   Ions in liquid ⁴He 

67.40.Kh   Thermodynamic properties 

67.40.Mj   First sound 

67.40.Pm   Transport processes, second and other sounds, and thermal counterflow; Kapitza resistance 

67.40.Rp   Films and weak link transport 

67.40.Vs   Vortices and turbulence 

67.40.Yv   Impurities and other defects 

67.55.-s   Normal phase of liquid ³He

67.55.Cx   Thermodynamic properties 

67.55.Fa   Hydrodynamics 

67.55.Hc   Transport properties 

67.55.Ig   Ions in normal liquid ³He 

67.55.Jd   Collective modes 

67.55.Lf   Impurities 

67.57.-z   Superfluid phase of liquid ³He

67.57.Bc   Thermodynamic properties 

67.57.De   Superflow and hydrodynamics 

67.57.Fg   Textures and vortices 

67.57.Gh   Ions in superfluid ³He

67.57.Hi   Transport properties 

67.57.Jj   Collective modes 

67.57.Lm   Spin dynamics 

67.57.Np   Behavior near interfaces 

67.57.Pq   Impurities 

67.60.-g   Mixed systems; liquid ³He, ⁴He mixtures

67.60.Dm   He I–³He 

67.60.Fp    He II–³He 

67.60.Hr   Dilute superfluid ³He in He II 

67.60.Js   Ions in liquid ³He–⁴He mixtures 

67.65.+z   Spin-polarized hydrogen and helium

67.70.+n   Films (including physical adsorption)

67.80.-s    Solid helium and related quantum crystals

67.80.Cx   Structure, lattice dynamics, and sound propagation 

67.80.Gb   Thermal properties 

67.80.Jd   Magnetic properties and nuclear magnetic resonance 

67.80.Mg   Defects, impurities, and diffusion 

67.90.+z   Other topics in quantum fluids and solids; liquid and solid helium (restricted to new topics in section 67)
 

68. Surfaces and interfaces; thin films and low-dimensional systems (structure and nonelectronic properties) (for surface and interface chemistry, see 82.65.+r, for surface magnetism, see 75.70.Rf)

68.03.-g Gas-liquid and vacuum-liquid interfaces

68.03.Cd Surface tension and related phenomena

68.03.Fg Evaporation and condensation

68.03.Hj Structure, measurements and simulations

68.03.Kn Dynamics (capillary waves)

68.05.-n Liquid-liquid interfaces 

68.05.Cf Structure, measurements and simulations 

68.05.Gh Interfacial properties of microemulsions

68.08.-p Liquid-solid interfaces

68.08.Bc Wetting

68.08.De Structure, measurements and simulations ... ... ...    Crystal growth, biomineralization, see 81.10.Dn, Fq

68.15.+e Liquid thin films

68.18.-g Langmuir-Blodgett films on liquids (for L–B films on solids, see 68.47.Pe)

68.18.Fg Structure: measurements and simulations

68.18.Jk Phase transitions

68.35.-p Solid surfaces and solid-solid interfaces: Structure and energetics 

68.35.Af Atomic scale friction

68.35.Ct Interface structure and roughness

68.35.Dv Composition, segregation; defects and impurities

68.35.Fx Diffusion; interface formation (see also 66.30 Diffusion in solids, for diffusion of adsorbates, see 68.43.Jk) 

68.35.Gy Mechanical properties; surface strains 

68.35.Iv Acoustical properties

68.35.Ja Surface and interface dynamics and vibrations ... ... ...   Solid-solid interfaces: transport and optical properties, see 73.40.-c and 78.20.-e respectively

68.35.Md Surface thermodynamics, surface energies (see also 05.70.Np Interface and surface thermodynamics in statistical physics, thermodynamics and nonlinear dynamical systems)

68.35.Np Adhesion

68.35.Rh Phase transitions and critical phenomena

68.37.-d Microscopy of surfaces, interfaces, and thin films

68.37.Ef Scanning tunneling microscopy (including chemistry induced with STM)

68.37.Hk Scanning electron microscopy (SEM) (including EBIC) 

68.37.Lp Transmission electron microscopy (TEM) (including STEM, HRTEM, etc.) 

68.37.Nq Low energy electron microscopy (LEEM)

68.37.Ps Atomic force microscopy (AFM)

68.37.Rt Magnetic force microscopy (MFM)

68.37.Tj Acoustic force microscopy

68.37.Uv Near-field scanning microscopy and spectroscopy

68.37.Vj Field emission and field-ion microscopy

68.37.Xy Scanning Auger microscopy, photoelectron microscopy

68.37.Yz X-ray microscopy

68.43.-h   Chemisorption/physisorption:  adsorbates on surfaces

68.43.Bc Ab initio calculations of adsorbate structure and reactions (see also 81.65.Mq Oxidation)

68.43.De Statistical mechanics of adsorbates 

68.43.Fg Adsorbate structure (binding sites, geometry)

68.43.Hn Structure of assemblies of adsorbates (two- and three-dimensional clustering)

68.43.Jk Diffusion of adsorbates, kinetics of coarsening and aggregation

68.43.Mn Adsorption/desorption kinetics

68.43.Pq Adsorbate vibrations

68.43.Rs Electron stimulated desorption

68.43.Tj Photon stimulated desorption

68.43.Vx Thermal desorption

68.47.-b Solid-gas/vacuum interfaces:  types of surfaces

68.47.De Metallic surfaces and metal alloys

68.47.Gh Oxide surfaces

68.47.Jn Clusters on oxide surfaces

68.47.Mn Polymer surfaces

68.47.Pe Langmuir-Blodgett films on solids, polymers on surfaces, biological molecules on surfaces

68.49.-h Surface characterization by particle-surface scattering

68.49.Bc Atom scattering from surfaces (diffraction and energy transfer)

68.49.Df Molecule scattering from surfaces (energy transfer, resonances, trapping)

68.49.Fg Cluster scattering from surfaces

68.49.Jk Electron scattering from surfaces

68.49.Sf Ion scattering from surfaces (charge transfer, sputtering, SIMS)

68.49.Uv X-ray standing waves... ... ...    Surface and interface electron states, see section 73.20.-i

... ...... ;   Electronic structure of adsorbates, see 73.20.Hb

... ... ...   Vibrational spectroscopy (IR, Raman, ATR), see 78.30.-j 

... ... ...    Electron spectroscopy (EELS, Auger, metastable quenching spectroscopy) see 79.20.-m

... ... ...   Photoelectron spectroscopy (XPS and UPS), see 79.60.-i 

... ... ...    Nonlinear spectroscopy (second harmonic, sum frequency generation etc.),  see 42.65.Ky 

... ... ...    Electron diffraction (LEED, RHEED) see 61.14.-x 

... ... ...    Surface enhanced spectroscopy, plasmons, see 73.20.Mf

... ... ...     Near-field spectroscopy, see 68.37.Uv

68.55.-a Thin film structure and morphology (for methods of thin film deposition, film growth and epitaxy, see 81.15.-z)

68.55.Ac Nucleation and growth:  microscopic aspects

68.55.Jk Structure and morphology; thickness; crystalline orientation and texture

68.55.Ln Defects and impurities:  doping, implantation, distribution, concentration, etc. (for diffusion of impurities, see 66.30.Jt)

68.55.Nq Composition and phase identification

68.60.- p Physical properties of thin films, nonelectronic

68.60.Bs Mechanical and acoustical properties

68.60.Dv Thermal stability; thermal effects

68.60.Wm Other nonelectronic physical properties

68.65.-k Low-dimensional, mesoscopic, and nanoscale systems: structure and nonelectronic properties (for structure of nanoscale materials, see 61.46.+w)

... ... ...    Growth of low-dimensional structures, see 81.16.-c

68.65.Ac Multilayers

68.65.Cd Superlattices

68.65.Fg Quantum wells

68.66.Hb Quantum dots 

68.66.La Quantum wires

68.90.+g Other topics in structure, and nonelectronic properties of surfaces and interfaces; thin films and low-dimensional structures (restricted to new topics in section 68)