**1999 PACS, 30. - 39.
**

**
Summary of Scheme
**

30. ATOMIC AND MOLECULAR PHYSICS (for physical chemistry, see
82)

**31. Electronic Structure of Atoms, Molecules and Their Ions: theory**

31.10.+z Theory of electronic structure, electronic transitions, and
chemical binding

31.15.-p Calculations and mathematical techniques in atomic and molecular
physics (excluding electron correlation calculations) (see also
02.70 computational techniques, in mathematical methods in
physics)

31.15.Ar Ab initio calculations

31.15.Bs Statistical model calculations (including Thomas-Fermi and
Thomas-Fermi-Dirac models)

31.15.Ct Semi-empirical and empirical calculations (differential overlap
Huckel, PPP methods, etc.)

31.15.Dv Coupled cluster theory

31.15.Ew Density-functional theory

31.15.Fx Finite-difference schemes

31.15.Gy Semiclassical methods

31.15.Hz Group theory

31.15.Ja Hyperspherical methods

31.15.Kb Path-integral methods

31.15.Lc Quasiparticle methods

31.15.Md Perturbation theory

31.15.Ne Self-consistent-field methods

31.15.Pf Variational techniques

31.15.Qg Molecular dynamics and other numerical methods

31.15.Rh Valence bond calculations

31.25.-v Electron correlation calculations for atoms and molecules

31.25.Eb Electron-correlation calculations for atoms and ions: ground state

31.25.Jf Electron-correlation calculations for atoms and ions: excited states

31.25.Nj Electron-correlation calculations for diatomic molecules

31.25.Qm Electron-correlation calculations for polyatomic molecules

31.30.-i Corrections to electronic structure

31.30.Gs Hyperfine interactions and isotope effects, Jahn-Teller effect

31.30.Jv Relativistic and quantum electrodynamic effects in atoms and molecules

31.50.+w Excited states

31.70.-f Effects of atomic and molecular interactions on electronic structure
(see also 34 Atomic and molecular collision processes and
interactions)

31.70.Dk Environmental and solvent effects

31.70.Hq Time-dependent phenomena: excitation and relaxation processes, and
reaction rates (for chemical kinetics aspects, see 82.20.R)

31.70.Ks Molecular solids

31.90.+s Other topics in the theory of the electronic structure of atoms,
molecules, and their ions (restricted to new topics in section 31)

**32. Atomic Properties and Interactions with Photons**

32.10.-f Properties of atoms and atomic ions

32.10.Bi Atomic masses, mass spectra, abundances, and isotopes: (for mass
spectroscopy, see 07.75)

32.10.Dk Electric and magnetic moments, polarizability

32.10.Fn Fine and hyperfine structure

32.10.Hq Ionization potentials, electron affinities

32.30.-r Atomic spectra

32.30.Bv Radio-frequency, microwave, and infrared spectra

32.30.Dx Magnetic resonance spectra

32.30.Jc Visible and ultraviolet spectra

32.30.Rj X-ray spectra

32.50.+d Fluorescence, phosphorescence (including quenching)

32.60.+i Zeeman and Stark effects

32.70.-n Intensities and shapes of atomic spectral lines

32.70.Cs Oscillator strengths, lifetimes, transition moments

32.70.Fw Absolute and relative intensities

32.70.Jz Line shapes, widths, and shifts

32.80.-t Photon interactions with atoms (see also 42.50 Quantum optics)

32.80.Bx Level crossing and optical pumping

32.80.Cy Atomic scattering, cross sections, and form factors; Compton
scattering

32.80.Dz Autoionization

32.80.Fb Photoionization of atoms and ions

32.80.Gc Photodetachment of atomic negative ions

32.80.Hd Auger effect and inner-shell excitation or ionization

32.80.Lg Mechanical effects of light on atoms, molecules, and ions

32.80.Pj Optical cooling of atoms; trapping

32.80.Qk Coherent control of atomic interactions with photons

32.80.Rm Multiphoton ionization and excitation to highly excited states (e.g.,
Rydberg states)

32.80.Wr Other multiphoton processes

32.80.Ys Weak-interaction effects in atoms

32.90.+a Other topics in atomic properties and interactions of atoms and ions
with photons

**33. Molecular Properties and Interactions with Photons**

33.15.-e Properties of molecules and molecular ions

33.15.Bh General molecular conformation and symmetry; stereochemistry

33.15.Dj Interatomic distances and angles

33.15.Fm Bond strengths, dissociation energies

33.15.Hp Barrier heights (internal rotation, inversion, rotational isomerism,
conformational dynamics)

33.15.Kr Electric and magnetic moments (and derivatives), polarizability,
and magnetic susceptibility

33.15.Mt Rotation, vibration, and vibration-rotation constants

33.15.Pw Fine and hyperfine structure

33.15.Ry Ionization potentials, electron affinities, molecular core binding
energy

33.15.Ta Mass spectra

33.15.Vb Correlation times in molecular dynamics

33.20.-t Molecular spectra

33.20.Bx Radio-frequency and microwave spectra

33.20.Ea Infrared spectra

33.20.Fb Raman and Rayleigh spectra (including optical scattering)

33.20.Kf Visible spectra

33.20.Lg Ultraviolet spectra

33.20.Ni Vacuum ultraviolet spectra

33.20.Rm X-ray spectra

33.20.Sn Rotational analysis

33.20.Tp Vibrational analysis

33.20.Vq Vibration-rotation analysis

33.20.Wr Vibronic, rovibronic, and rotation-electron-spin interactions

33.25.+k Nuclear resonance and relaxation

33.35.+r Electron resonance and relaxation

33.40.+f Multiple resonances (including double and higher-order resonance
processes, such as double nuclear magnetic resonance, electron
double resonance, and microwave optical double resonance) (see also
76.70 Magnetic double resonances and cross effects in condensed
matter)

33.45.+x Mossbauer spectra

33.50.-j Fluorescence and phosphorescence; radiationless transitions, quenching
(intersystem crossing, internal conversion) (for energy transfer,
see also 34)

33.50.Dq Fluorescence and phosphorescence spectra

33.50.Hv Radiationless transitions, quenching

33.55.-b Optical activity and dichroism; magnetooptical and electrooptical
spectra

33.55.Ad Optical activity, optical rotation; circular dichroism

33.55.Be Zeeman and Stark effects

33.55.Fi Other magnetooptical and electrooptical effects

33.60.-q Photoelectron spectra

33.60.Cv Ultraviolet and vacuum ultraviolet photoelectron spectra

33.60.Fy X-ray photoelectron spectra

33.70.-w Intensities and shapes of molecular spectral lines and bands

33.70.Ca Oscillator and band strengths, lifetimes, transition moments, and
Franck-Condon factors

33.70.Fd Absolute and relative line and band intensities

33.70.Jg Line and band widths, shapes, and shifts

33.80.-b Photon interactions with molecules (see also 42.50 Quantum optics)

33.80.Be Level crossing and optical pumping

33.80.Eh Autoionization, photoionization, and photodetachment

33.80.Gj Diffuse spectra; predissociation, photodissociation

33.80.Ps Optical cooling of molecules; trapping

33.80.Rv Multiphoton ionization and excitation to highly excited states (e.g.,
Rydberg states)

33.80.Wz Other multiphoton processes

33.90.+h Other topics in molecular properties and interactions with photons
(restricted to new topics in section 33)

**34. Atomic and Molecular Collision Processes and Interactions**

34.10.+x General theories and models of atomic and molecular collisions and
interactions (including statistical theories, transition state,
stochastic and trajectory models, etc.)

34.20.-b Interatomic and intermolecular potentials and forces, potential energy
surfaces for collisions

34.20.Cf Interatomic potentials and forces

34.20.Gj Intermolecular and atom-molecule potentials and forces

34.20.Mq Potential energy surfaces for collisions (see also 82.20.K Potential
energy surfaces for chemical reactions)

34.30.+h Intramolecular energy transfer; intramolecular dynamics; dynamics of
van der Waals molecules

34.50.-s Scattering of atoms, molecules, and ions

34.50.Bw Energy loss and stopping power

34.50.Dy Interactions of atoms, molecules, and their ions with surfaces; photon
and electron emission; neutralization of ions

34.50.Ez Rotational and vibrational energy transfer

34.50.Fa Electronic excitation and ionization of atoms (including beam-foil
excitation and ionization)

34.50.Gb Electronic excitation and ionization of molecules; intermediate
molecular states (including lifetimes, state mixing, etc.)

34.50.Lf Chemical reactions, energy disposal, and angular distribution, as
studied by atomic and molecular beams (for atomic and molecular
beam reactions, see 82.40.D)

34.50.Pi State-to-state scattering analyses

34.50.Rk Laser-modified scattering and reactions

34.60.+z Scattering in highly excited states (e.g., Rydberg states)

34.70.+e Charge transfer (for charge transfer reactions, see 82.30.F)

34.80.-i Electron scattering

34.80.Bm Elastic scattering of electrons by atoms and molecules

34.80.Dp Atomic excitation and ionization by electron impact

34.80.Gs Molecular excitation and ionization by electron impact

34.80.Ht Dissociation and dissociative attachment by electron impact

34.80.Kw Electron-ion scattering; excitation and ionization

34.80.Lx Electron-ion recombination and electron attachment

34.80.My Fundamental electron inelastic processes in weakly ionized gases

34.80.Nz Spin dependence of cross sections; polarized electron beam experiments

34.80.Pa Coherence and correlation in electron scattering

34.80.Qb Laser-modified scattering

34.85.+x Positron scattering

34.90.+q Other topics in atomic and molecular collision processes and
interactions (restricted to new topics in section 34)

**36. Studies of Special Atoms, Molecules, and Their Ions; Clusters**

36.10.-k Exotic atoms and molecules (containing mesons, muons, and other
unusual particles)

36.10.Dr Positronium, muonium, muonic atoms and molecules

36.10.Gv Mesonic atoms and molecules, hyperonic atoms and molecules

36.20.-r Macromolecules and polymer molecules (for polymer reactions and
polymerization, see 82.35; for biological macromolecules and polymers,
see 87.15)

36.20.Cw Molecular weights, dispersity

36.20.Ey Conformation (statistics and dynamics)

36.20.Fz Constitution (chains and sequences)

36.20.Hb Configuration (bonds, dimensions)

36.20.Kd Electronic structure and spectra

36.20.Ng Vibrational and rotational structure, infrared and Raman spectra

36.40.-c Atomic and molecular clusters: (see also 61.46 Solid clusters and
nanoparticles)

36.40.Cg Electronic and magnetic properties of clusters

36.40.Ei Phase transitions in clusters

36.40.Gk Plasma and collective effects in clusters

36.40.Jn Reactivity of clusters

36.40.Mr Spectroscopy and geometrical structure of clusters

36.40.Qv Stability and fragmentation of clusters

36.40.Sx Diffusion and dynamics of clusters

36.40.Vz Optical properties of clusters

36.40.Wa Charged clusters

36.90.+f Other special atoms, molecules, ions, and clusters (restricted to
new topics in section 36)

**39. Instrumentation and Techniques for Atomic and Molecular Physics**

39.10.+j Atomic and molecular beam sources and techniques

39.20.+q Atom interferometry techniques: (see also 03.75.Dg Atom and neutron
interferometry)

39.30.+w Spectroscopic techniques (see also 78.47
Time-resolved optical spectroscopies and other ultrafast optical measurements
in condensed matter)

39.90.+d Other instrumentation and techniques for atomic and molecular
physics (restricted to new topics in section 39)