revised 11/98

1999 PACS, 00. - 09.

01. Communication, education, history, and philosophy
02. Mathematical methods in physics
03. Quantum mechanics, field theories, and special relativity
04. General relativity and gravitation
05. Statistical physics and thermodynamics, and nonlinear dynamical systems
06. Metrology, measurements, and laboratory procedures
07. Specific instrumentation and techniques of general use in physics
11. General theory of fields and particles
12. Specific theories and interaction models; particle systematics
13. Specific reactions and phenomenology
14. Properties of specific particles
21. Nuclear structure
23. Radioactive decay and in-beam spectroscopy
24. Nuclear reactions: general
25. Nuclear reactions: specific reactions
27. Properties of specific nuclei listed by mass ranges
28. Nuclear engineering and nuclear power studies
29. Experimental methods and instrumentation for elementary-particle and nuclear physics
31. Electronic structure of atoms and molecules: theory
32. Atomic spectra and interactions with photons
33. Molecular spectra and interactions of molecules with photons
34. Atomic and molecular collision processes and interactions
35. Experimentally derived information on atoms and molecules; instrumentation and techniques
36. Studies of special atoms and molecules
41. Electromagnetism; electron and ion optics
42. Optics
43. Acoustics
44. Heat transfer, thermal and thermodynamic processes
45. Classical mechanics of discrete systems
46. Continuum mechanics of solids
47. Fluid dynamics
51. Kinetic and transport theory of fluids; physical properties of gases
52. The physics of plasmas and electric discharges
61. Structure of solids and liquids; crystallography
62. Mechanical and acoustical properties of condensed matter
63. Lattice dynamics
64. Equations of state, phase equilibria, and phase transitions
65. Thermal properties of condensed matter
66. Transport properties of condensed matter (nonelectronic)
67. Quantum fluids and solids; liquid and solid helium
68. Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties)
71. Electronic structure
72. Electronic transport in condensed matter
73. Electronic structure and electrical properties of surfaces, interfaces, and thin films
74. Superconductivity
75. Magnetic properties and materials
76. Magnetic resonances and relaxations in condensed matter, Mossbauer effect
77. Dielectrics, piezoelectrics, and ferroelectrics and their properties
78. Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation
79. Electron and ion emission by liquids and solids; impact phenomena
81. Materials science
82. Physical chemistry
83. Rheology
84. Electromagnetic technology
85. Electronic and magnetic devices
87. Biophysics and medical physics
89. Topics of general interest to physicists
91. Solid Earth physics
92. Hydrospheric and atmospheric geophysics
93. Geophysical observations, instrumentation, and techniques
94. Aeronomy and magnetospheric physics
95. Fundamental astronomy and astrophysics; instrumentation, techniques and astronomical observations
96. Solar System
97. Stars
98. Stellar systems; galactic and extragalactic objects and systems; the Universe

01. Communication, Education, History, and Philosophy
01.10.-m Announcements, news, and organizational activities
01.10.Cr Announcements, news, and awards
01.10.Fv Conferences, lectures, and institutes
01.10.Hx Physics organizational activities
01.20.+x Communication forms and techniques (written, oral, electronic, etc.)
01.30.-y Physics literature and publications
01.30.Bb Publications of lectures (advanced institutes, summer schools, etc.)
01.30.Cc Conference proceedings
01.30.Ee Monographs and collections
01.30.Kj Handbooks, dictionaries, tables, and data compilations
01.30.Mm Textbooks for graduates and researchers
01.30.Pp Textbooks for undergraduates
01.30.Rr Surveys and tutorial papers; resource letters
01.30.Tt Bibliographies
01.30.Vv Book reviews
01.30.Xx Publications in electronic media (for the topic of electronic publishing, see 01.20)
01.40.-d Education
01.40.Di Course design and evaluation
01.40.Ej Science in elementary and secondary school
01.40.Fk Physics education research (cognition, problem solving, etc.)
01.40.Gm Curricula; teaching methods, strategies, theory of testing, evaluation
01.40.Jp Teacher training
01.50.-i Educational aids
01.50.Fr Audio and visual aids, films
01.50.Ht Instructional computer use
01.50.Kw Techniques of testing
01.50.Lc Laboratory computer use (see also 01.50.P)
01.50.My Demonstration experiments and apparatus
01.50.Pa Laboratory experiments and apparatus (see also 01.50.L)
01.50.Qb Laboratory course design, organization, and evaluation
01.50.Wg Physics of toys
01.52.+r National and international laboratory facilities
01.55.+b General physics
01.60.+q Biographies, tributes, personal notes, and obituaries
01.65.+g History of science
01.70.+w Philosophy of science
01.75.+m Science and society (for science and government, see 01.78)
01.78.+p Science and government (funding, politics, etc.)
01.80.+b Physics of sports
01.90.+g Other topics of general interest (restricted to new topics in section 01)
02. Mathematical Methods in Physics
02.10.-v Logic, set theory, and algebra
02.10.By Logic and foundations
02.10.Cz Set theory
02.10.Eb Combinatorics
02.10.Gd Order, lattices, and ordered algebraic structures
02.10.Jf General mathematical systems
02.10.Lh Number theory
02.10.Nj Algebraic number theory, field theory, and polynomials
02.10.Pk Commutative rings and algebras
02.10.Rn Algebraic geometry
02.10.Sp Linear and multilinear algebra; matrix theory (finite and infinite)
02.10.Tq Associative rings and algebras
02.10.Vr Nonassociative rings and algebras
02.10.Ws Category theory and homological algebra
02.20.-a Group theory (for algebraic methods in quantum mechanics, see 03.65.F; for symmetries in elementary particle physics, see
02.20.Df Finite groups
02.20.Fh Infinite groups
02.20.Hj Classical linear algebraic groups
02.20.Km Abelian groups
02.20.Mp Semigroups
02.20.Nq Topological groups, general
02.20.Qs General properties, structure, and representation of Lie groups
02.20.Rt Discrete subgroups of Lie groups
02.20.Sv Lie algebras of Lie groups
02.20.Tw Infinite-dimensional Lie groups
02.30.-f Function theory, analysis
02.30.Bi Real functions
02.30.Cj Measure and integration
02.30.Dk Functions of a complex variable
02.30.Em Potential theory
02.30.Fn Several complex variables and analytic spaces
02.30.Gp Special functions
02.30.Hq Ordinary differential equations
02.30.Jr Partial differential equations
02.30.Ks Delay and functional equations
02.30.Lt Sequences, series, and summability
02.30.Mv Approximations and expansions
02.30.Nw Fourier analysis
02.30.Px Abstract harmonic analysis
02.30.Qy Integral transforms and operational calculus
02.30.Rz Integral equations
02.30.Sa Functional analysis
02.30.Tb Operator theory
02.30.Wd Calculus of variations and optimal control
02.40.-k Geometry, differential geometry, and topology (see also 04 Relativity and gravitation)
02.40.Dr Euclidean and projective geometries
02.40.Ft Convex sets and geometric inequalities
02.40.Hw Classical differential geometry
02.40.Ky Riemannian geometries
02.40.Ma Global differential geometry
02.40.Pc General topology
02.40.Re Algebraic topology
02.40.Sf Manifolds and cell complexes
02.40.Vh Global analysis and analysis on manifolds
02.50.-r Probability theory, stochastic processes, and statistics (see also 05 Statistical physics)
02.50.Cw Probability theory
02.50.Ey Stochastic processes
02.50.Fz Stochastic analysis
02.50.Ga Markov processes
02.50.Hb Queuing theory
02.50.Kd Foundations of statistics; sufficiency
02.50.Le Decision theory and game theory
02.50.Ng Distribution theory and Monte Carlo studies
02.50.Ph Parametric inference
02.50.Rj Nonparametric inference
02.50.Sk Multivariate analysis
02.50.Vn Linear inference
02.50.Wp Inference from stochastic processes
02.60.-x Numerical approximation and analysis
02.60.Cb Numerical simulation; solution of equations
02.60.Dc Numerical linear algebra
02.60.Ed Interpolation; curve fitting
02.60.Gf Algorithms for functional approximation
02.60.Jh Numerical differentiation and integration
02.60.Lj Ordinary and partial differential equations; boundary value problems
02.60.Nm Integral and integrodifferential equations
02.60.Pn Numerical optimization
02.70.-c Computational techniques
02.70.Bf Finite-difference methods
02.70.Dh Finite-element and Galerkin methods
02.70.Fj Finite-volume methods
02.70.Hm Spectral methods
02.70.Jn Collocation methods
02.70.Lq Monte Carlo and statistical methods
02.70.Ns Molecular dynamics and particle methods
02.70.Pt Boundary-integral methods
02.90.+p Other topics in mathematical methods in physics (restricted to new topics in section 02)
03. Quantum mechanics, field theories, and special relativity (see also 11 General theory of fields and particles)
03.30.+p Special relativity
03.50.-z Classical field theories
03.50.De Classical electromagnetism, Maxwell equations (for applied classical electromagnetism, see 41.20)
03.50.De Maxwell theory: general mathematical aspects (for applied classical electrodynamics, see 41)
03.50.Kk Other special classical field theories
03.65.-w Quantum mechanics (see also 05.30 Quantum statistical mechanics)
03.65.Bz Foundations, theory of measurement, miscellaneous theories (including Aharonov-Bohm effect, Bell inequalities, Berry's phase)
03.65.Ca Formalism
03.65.Db Functional analytical methods
03.65.Fd Algebraic methods (see also 02.20 Group theory)
03.65.Ge Solutions of wave equations: bound states
03.65.Nk Nonrelativistic scattering theory (see also 03.80 General theory of scattering)
03.65.Pm Relativistic wave equations
03.65.Sq Semiclassical theories and applications
03.67.-a Quantum information
03.67.Dd Quantum cryptography
03.67.Hk Quantum communication
03.67.Lx Quantum computation
03.70.+k Theory of quantized fields (see also 11.10 Field theory)
03.75.-b Matter waves
03.75.Be Atom and neutron optics
03.75.Dg Atom and neutron interferometry
03.75.Fi Phase coherent atomic ensembles; quantum condensation phenomena
04. General Relativity and Gravitation (for relativistic cosmology, see 98.80.H)
04.20.-q Classical general relativity (see also 02.40 Geometry and topology)
04.20.Cv Fundamental problems and general formalism
04.20.Dw Singularities and cosmic censorship
04.20.Ex Initial value problem, existence and uniqueness of solutions
04.20.Fy Canonical formalism, Lagrangians, and variational principles
04.20.Gz Spacetime topology, causal structure, spinor structure
04.20.Ha Asymptotic structure
04.20.Jb Exact solutions
04.25.-g Approximation methods; equations of motion
04.25.Dm Numerical relativity
04.25.Nx Post-Newtonian approximation; perturbation theory; related approximations
04.30.-w Gravitational waves: theory
04.30.Db Wave generation and sources
04.30.Nk Wave propagation and interactions
04.40.-b Self-gravitating systems; continuous media and classical fields in curved spacetime
04.40.Dg Relativistic stars: structure, stability, and oscillations (for relativistic astrophysics, see 95.30.S)
04.40.Nr Einstein-Maxwell spacetimes, spacetimes with fluids, radiation or classical fields
04.50.+h Gravity in more than four dimensions, Kaluza-Klein theory, unified field theories, alternative theories of gravity (see also 11.25.M Compactification and four-dimensional models)
04.60.-m Quantum gravity (see also 98.80.H Quantum cosmology)
04.60.Ds Canonical quantization
04.60.Gw Covariant and sum-over-histories quantization
04.60.Kz Lower dimensional models; minisuperspace models
04.60.Nc Lattice and discrete methods
04.62.+v Quantum field theory in curved spacetime
04.65.+e Supergravity (see also 12.60.J Supersymmetric models)
04.70.-s Physics of black holes (for astrophysics of black holes, see 97.60.L)
04.70.Bw Classical black holes
04.70.Dy Quantum aspects of black holes, evaporation, thermodynamics
04.80.-y Experimental studies of gravity
04.80.Cc Experimental tests of gravitational theories
04.80.Nn Gravitational wave detectors and experiments (see also 95.55.Y in Astronomical instrumentation)
04.90.+e Other topics in general relativity and gravitation (restricted to new topics in section 04)
05. Statistical physics, thermodynamics, and nonlinear dynamical systems (see also 02.50 Probability theory, stochastic processes, and statistics)
05.10.-a Computational methods in statistical physics and nonlinear dynamics (see also 02.70 in mathematical methods in physics)
05.10.Cc Renormalization group methods
05.10.Gg Stochastic analysis methods (Fokker-Planck, Langevin, etc.)
05.10.Ln Monte Carlo methods
General theory in fluid dynamics)
05.20.-y Classical statistical mechanics
05.20.Dd Kinetic theory
05.20.Gg Classical ensemble theory
05.20.Jj Statistical mechanics of classical fluids (see also
47.10 05.30.-d Quantum statistical mechanics
05.30.Ch Quantum ensemble theory
05.30.Fk Fermion systems and electron gas
05.30.Jp Boson systems
05.30.Pr Fractional statistics systems (anyons, etc.)
05.40.-a Fluctuation phenomena, random processes, noise, and Brownian motion
05.40.Ca Noise
05.40.Fb Random walks and Levy flights
05.40.Jc Brownian motion
05.45.-a Nonlinear dynamics and nonlinear dynamical systems (see also 45 Classical mechanics of discrete systems)
05.45.Ac Low-dimensional chaos
05.45.Df Fractals (see also 47.53 Fractals in Fluid dynamics)
05.45.Gg Control of chaos, applications of chaos
05.45.Jn High-dimensional chaos
05.45.Mt Semiclassical chaos ("quantum chaos")
05.45.Pq Numerical simulations of chaotic models
05.45.Ra Coupled map lattices
05.45.Tp Time series analysis
05.45.Vx Communication using chaos
05.45.Xt Synchronization; coupled oscillators
05.45.Yv Solitons (see 52.35.S for solitons in Plasma; 42.50.M, 42.65,T, 42.81.D for solitons in Optics)
05.50.+q Lattice theory and statistics (Ising, Potts, etc.) (see also 64.60.C Order-disorder transformations and statistical mechanics of model systems and 75.10.H Classical spin models)
05.60.-k Transport processes
05.60.Cd Classical transport
05.60.Gg Quantum transport
05.65.+b Self-organized systems (see also 45.70 in classical mechanics of discrete systems)
05.70.-a Thermodynamics (see also 64 Equations of state, phase equilibria, and phase transitions, and 65 Thermal properties of condensed matter; for chemical thermodynamics, see 82.60)
05.70.Ce Thermodynamic functions and equations of state
05.70.Fh Phase transitions: general studies
05.70.Jk Critical point phenomena
05.70.Ln Nonequilibrium thermodynamics, irreversible processes (see also 82.20.M Nonequilibrium kinetics, and 82.40.B Oscillations, chaos, and bifurcations in homogeneous and nonequilibrium reactors)
05.70.Np Interface and surface thermodynamics (see also 82.65.D Thermodynamics of surfaces and interfaces in physical chemistry)
05.90.+m Other topics in statistical physics, thermodynamics, and nonlinear dynamical systems (restricted to new topics in section 05)
06. Metrology, Measurements, and Laboratory Procedures
06.20.-f Metrology
06.20.Dk Measurement and error theory
06.20.Fn Units and standards
06.20.Jr Determination of fundamental constants
06.30.-k Measurements common to several branches of physics and astronomy
06.30.Bp Spatial dimensions (e.g., position, lengths, volume, angles, displacements, including nanometer-scale displacements)
06.30.Dr Mass and density
06.30.Ft Time and frequency
06.30.Gv Velocity, acceleration, and rotation
06.60.-c Laboratory procedures
06.60.Ei Sample preparation (including design of sample holders)
06.60.Jn High-speed techniques (microsecond to femtosecond)
06.60.Mr Testing and inspecting procedures
06.60.Sx Positioning and alignment; manipulating, remote handling
06.60.Vz Workshop procedures (welding, machining, lubrication, bearings, etc.)
06.60.Wa Laboratory safety procedures
06.90.+v Other topics in metrology, measurements, and laboratory procedures (restricted to new topics in section 06)
07. Instruments, Apparatus, Components, and Techniques common to several Branches of physics and astronomy
7.05.-t Computers in experimental physics
***** Computers in physics education, see 01.50.H and 01.50.L
***** Computational techniques, see 02.70 - in mathematical methods in physic s
***** Quantum computation, see 03.67.L in quantum mechanics
07.05.Bx Computer systems: hardware, operating systems, computer languages, and utilities
07.05.Dz Control systems
07.05.Fb Design of experiments
07.05.Hd Data acquisition: hardware and software
07.05.Kf Data analysis: algorithms and implementation; data management
07.05.Mh Neural networks, fuzzy logic, artificial intelligence
07.05.Pj Image processing: (see also
42.30.V in optics)
07.05.Rm Data presentation and visualization: algorithms and implementation
07.05.Tp Computer modeling and simulation
07.05.Wr Computer interfaces
07.07.-a General equipment and techniques
07.07.Df Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing
07.07.Hj Display and recording equipment, oscilloscopes, TV cameras, etc.
07.07.Mp Transducers
07.07.Tw Servo and control equipment; robots
07.07.Vx Hygrometers
07.10.-h Mechanical instruments, equipment, and techniques
07.10.Cm Micromechanical devices and systems: (see also 85.42 Nanotechnology)
07.10.Fq Vibration isolation
07.10.Lw Balance systems, tensile machines, etc.
07.10.Pz Instruments for strain, force, and torque
07.20.-n Thermal instruments, apparatus, and techniques
07.20.Dt Thermometry
07.20.Fw Calorimetry
07.20.Hy Furnaces; heaters
07.20.Ka High-temperature techniques and instrumentation; pyrometry
07.20.Mc Cryogenics, refrigerators; low-temperature techniques
07.20.Pe Heat engines; heat pumps
07.30.-t Vacuum apparatus and techniques (see also 47.45 Rarefied gas dynamics)
07.30.Bx Degasification, residual gas
07.30.Cy Vacuum pumps
07.30.Dz Vacuum gauges
07.30.Hd Vacuum testing methods; leak detectors
07.30.Kf Vacuum chambers, auxiliary apparatus, and materials
07.35.+k High-pressure apparatus and techniques; shock tubes; diamond anvil cells
07.50.-e Electrical and electronic components, instruments, and techniques
07.50.Ek Circuits and circuit components: (see also 85.20--in electrical and magnetic devices)
07.50.Hp Electrical noise and shielding, interference
07.50.Ls Electrometers
07.50.Qx Signal processing electronics
07.55.-w Magnetic components, instruments and techniques
07.55.Db Generation of magnetic fields; magnets: (see also 85.70.N--in magnetic devices)
07.55.Ge Magnetometers for magnetic field measurements
07.55.Jg Magnetometers for susceptibility, magnetic moment, and magnetization measurements
07.55.Nk Magnetic shielding in instruments
07.57.-c Infrared, submillimeter wave, microwave and radiowave instruments, equipment and techniques (for infrared and radio telescopes, see 95.55)
07.57.Hm Infrared, submillimeter wave, microwave, and radiowave sources
07.57.Kp Bolometer; infrared, submillimeter wave, microwave, and radiowave receivers and detectors (see also 85.60.G Photodetectors and infrared detectors)
07.57.Pt Submillimeter wave, microwave and radiowave spectrometers; magnetic resonance spectrometers, auxiliary equipment, and techniques
07.57.Ty Infrared spectrometers, auxiliary equipment, and techniques
07.60.-j Optical instruments, equipment, and techniques
***** Optical sources, see 42.72
***** Optical elements, devices, and systems 42.79
***** Optoelecctronic devices 85.60
***** Optical telescopes, see 95.55
07.60.Dq Photometers, radiometers, and colorimeters
07.60.Fs Polarimeters and ellipsometers
07.60.Hv Refractometers and reflectometers
07.60.Ly Interferometers
07.60.Pb Conventional optical microscopes: (for near-field scanning optical microscopes, see 07.79.B)
07.60.Rd Visible and ultraviolet spectrometers
07.60.Vg Fiber-optic instruments (see also 42.81 Fiber optics)
07.64.+z Acoustic instruments, equipment, and techniques: (see also Acoustic Appendix)
07.68.+m Photography, photographic instruments and techniques; xerography
07.75.+h Mass spectrometers and related techniques
07.77.-n Atomic, molecular, and charged-particle sources and detectors
07.77.Gx Atomic and molecular beam sources and detectors
07.77.Ka Charged-particle beam sources and detectors
07.78.+s Electron, positron, and ion microscopes, electron diffractometers, and related techniques
07.79.-v Scanning probe microscopes: components and techniques
07.79.Cz Scanning tunneling microscopes
07.79.Fc Near-field scanning optical microscopes
07.79.Lh Atomic force microscopes
07.79.Pk Magnetic force microscopes
07.79.Sp Friction force microscopes
07.81.+a Electron, ion spectrometers, and related techniques
07.85.-m X- and gamma-ray instruments and techniques
07.85.Fv X- and gamma-ray sources, mirrors, gratings, and detectors
07.85.Jy Diffractometers
07.85.Nc X- and gamma-ray spectrometers
07.85.Qe Synchrotron radiation instrumentation
07.85,Tt X-ray microscopes
07.87.+v Spaceborne and space research instruments, apparatus, and components (satellites, space vehicles, etc.)
07.88.+y Instruments for environmental pollution measurements
07.89.+b Environmental effects on instruments (e.g., radiation and pollution effects)
07.90.+c Other topics in instruments, apparatus, components, and techniques common to several branches of physics and astronomy (restricted to new topics in section 07)