EDITORIAL

Editors of Molecular Physics 1958 – 2016

Figure 1. Lunch for Past Editors and Advisory Board Members of Molecular Physics, Exeter College Oxford, 29 April 2016. Front row: Andrew Orr-Ewing, Dominic Tildesley, Wenjian Liu, Ian Mills, John Rowlinson, George Jackson, and Tim Softley. Second row: Hans-Joachim Werner, Amparo Galindo, David Buckingham, Ian McDonald, Ruth Lynden-Bell, Frédéric Merkt, and David Tozer. Third row: Joan van der Waals, Laurence Barron, Peter Hore, Bob Evans, and Gunnar Jeschke. Back row: Geoffrey Luckhurst, Martin Quack, Fred Manby, and Trygve Helgaker.

As the founding Editors of Molecular Physics, H. Christopher Longuet-Higgins (University of Cambridge) and Joan H. van der Waals (Koninklijke Shell Laboratory, Amsterdam) remarked in their opening editorial, the discipline of molecular physics occupies a key position at the frontier between the physical sciences (chemistry and physics), molecular engineering and now increasingly biology. The strength of a molecular approach is based on understanding and describing the link between the structure and properties of molecules and the behaviour of the material at the macroscopic level. The perspective of Longuet-Higgins came from a firm grounding in theoretical chemistry and spectroscopy (he

undertook his doctoral training with Charles Coulson in the early days of valence bond theory), and was complementary to that of van der Waals which was shaped by the long tradition of the Dutch school in thermodynamics, statistical mechanics, and phase equilibria; the late Nobel Prize winner Johannes D. van der Waals was a nephew of the great-grandfather of Joan van der Waals (Joan is Johannes' first cousin twice removed). The research contributions published in the journal to this day very much retain this important mix of quantum chemistry, spectroscopy, thermodynamics, and statistical mechanics.

Table 1. Editors of Molecular Physics from 1958 to 2016.

At its foundation the first Editorial Board of the journal comprised a distinguished collection of eminent scientists working in

different branches of this boundary discipline: J. Bjerrum (Copenhagen), G. Careri (Padua), C. A. Coulson (Oxford) F. H. C. Crick

Term Editor Location Role 1958-1961 H.C.Longuet-Higgins University of Cambridge Editor 1958-1963 J. H. van der Waals Koninklijke Shell Laboratory, Amsterdam Associate Editor 1962-1967 G. S. Rushbrooke University of Newcastle Editor 1963-1968 J. P. Colpa Koninklijke Shell Laboratory, Amsterdam Associate Editor 1967-1973 J. S. Rowlinson Imperial College London Acting Editor/Associate Editor 1968-1972 A. D. Buckingham University of Cambridge Editor 1969-1970 L. Salem University of Paris-Sud, Orsay Associate Editor 1971 M. P. Bogaard University of Cambridge Assistant Editor 1972 L. D. Barron University of Cambridge Assistant Editor 1973-1977 I. M. Mills University of Reading Editor 1973 P. D. Mallinson University of Reading Assistant Editor 1973-1978 J. G. Powles University of Kent Associate Editor 1973-1977 A. G. Robiette University of Reading Assistant Editor 1976-1981 G. R. Luckhurst University of Southampton Associate Editor/Editor 1978-1983 R. E. Moss University of Southampton Assistant Editor/Associate Editor 1979-1985 I. R. McDonald Royal Holloway/University of Cambridge Associate Editor/Editor 1982-1985 K. J. Packer University of East Anglia Associate Editor 1984-1987 M. Quack ETH Zurich Associate Editor/Editor 1986-1991 R. F. Barrow University of Oxford Editor /Chair 1986-1992 D. J. Tildesley University of Southampton Associate Editor/Editor/Chair 1987-1991 A. Pines University of California, Berkeley Editor 1988-1992 A. Wokaun University of Bayreuth Editor 1991-1995 B. J. Howard University of Oxford Editor/Chair 1991-2005 H. F. Schaefer III University of Georgia Editor/Chair 1992-1994 I. R. McDonald University of Cambridge Editor 1994-1997 G. Jackson University of Sheffield Editor 1995-2007 N. C. Handy University of Cambridge Editor 1995-2004 I. M. Mills University of Reading Editor 1996-2002 A. Bauder ETH Zurich Editor 1998-2003 R. M. Lynden-Bell The Queen's University, Belfast Editor 2002-2007 F. Merkt ETH Zurich Editor 2003-2013 J.-P. Hansen University of Cambridge Editor/Chair 2004-2016 T. P. Softley University of Oxford/University of

Birmingham Editor/Chair

2006-date M. P. Head-Gordon University of California, Berkeley Editor 2007-2010 V. Sandoghdar ETH Zurich Editor 2008-2013 H. J. Werner University of Stuttgart Editor 2011-date G. Jeschke ETH Zurich Editor 2013-date T. U. Helgaker University of Oslo Editor 2013-date G. Jackson Imperial College London Editor/Chair 2016-date W. Liu Peking University Editor

(Cambridge), P. J. W. Debye (Cornell), D. Hadzi (Ljubljana), O. Hassel (Oslo), W. Heitler (Zurich), J. O. Hirschfelder (Wisconsin), D. F. Hornig (Princeton), J. A. A. Ketelaar (Amsterdam), J. G. Kirkwood (Yale), R. Kronig (Delft), J. W. Linnett (Oxford), A. Liquori (Rome), K. Lonsdale (London), P.-O. Löwdin (Uppsala), M. Magat (Paris), W. Moffit (Harvard), R. S. Mulliken (Chicago), A. Münster (Frankfurt), L. J. Oosterhoff (Leiden), L. E. Orgel (Cambridge), J. A. Pople (Cambridge), I. Prigogine (Brussels), R. E. Richards (Oxford), J. S. Rowlinson (Manchester), G. S. Rushbrooke (Newcastle), L. E. Sutton (Oxford), H. W. Thompson (Oxford), and B. Vodar (Paris).

Together with the Editorial Board, Longuet-Higgins and van der Waals launched Molecular Physics in 1958, welcoming scientific papers on: molecular structure and dynamics; the electric and magnetic properties of molecules (including the processes of molecular excitation, ionization, and dissociation); and the equilibrium, transport, and relaxation properties of molecular assemblies.

Guided by its Editors (see Table 1 for a complete list) and Editorial/Advisory Board, the journal has published contributions which now encompass even broader areas of chemical physics, molecular engineering, and biomolecular sciences, including the classical or first-principles molecular simulation of macroscopic systems which was not possible at the time of the journal’s launch.

A testament to the breadth and depth of the scientific research disseminated in Molecular Physics since its inception can be gleaned from the collection of most cited papers in the journal (see Table 2 for a list of the 50 top-cited papers to October 2016). It is not the intention here to discuss the numerous attributes of this large body of research in any detail; a selection of five papers from the top

ten in the separate areas of quantum chemistry, spectroscopy, molecular simulation and statistical thermodynamics are mentioned briefly as examples of the types of seminal contribution published in the journal.

The most cited paper published in Molecular Physics to date was presented by Boys and Bernardi in 1970 to address the quantum-mechanical basis set superposition error (BSSE) in the calculation of non-covalent interactions (such as hydrogen bonding, physical adsorption or solvation); the BBSE caused by the size imbalance in the basis sets used to describe the corresponding subsystems can be reduced by employing the counterpoise procedure proposed by Boys and Bernandi with the introduction of so-called “ghost” orbitals. Though there has been some controversy concerning its effectiveness, the counterpoise procedure of Boys and Bernandi is still widely used.

The natural ensemble arising from the traditional solution of Newton's equations of motion in molecular-dynamics simulations is the microcanonical (NVE) ensemble, where the total energy of the system is conserved. For practical purposes, it is often more convenient to simulate a system at constant temperature, corresponding to the canonical ensemble (NVT), than at constant energy. In his paper of 1984 (number 2 in Table 2), Nosé presented an efficient and rigorous methodology for molecular-dynamics simulation at constant temperature (and also at constant pressure); in this approach the energy of the system is allowed to fluctuate by exchanging heat with an external heat reservoir, and an associated potential energy contribution is introduced to set the temperature at the desired value. The Nosé temperature-control algorithm was further refined by Hoover in 1985, and the Nosé-Hoover thermostat is now a standard option in off-the-shelf simulation packages such as DL_POLY, GROMACS, and LAMMPS.

Authors Title Reference Citations

1 S. F. BOYS and F. BERNARDI

CALCULATION OF SMALL MOLECULAR INTERACTIONS BY DIFFERENCES OF SEPARATE TOTAL ENERGIES: SOME PROCEDURES WITH REDUCED ERRORS

19, 553 (1970) 13586

2 S. NOSÉ A MOLECULAR-DYNAMICS METHOD FOR SIMULATIONS IN THE CANONICAL ENSEMBLE

52, 255 (1984) 4097

3 R. DITCHFIELD SELF-CONSISTENT PERTURBATION-THEORY OF DIAMAGNETISM: 1. GAUGE-INVARIANT LCAO METHOD FOR NMR CHEMICAL SHIFTS

27, 789 (1974) 2913

4 P. PULAY AB INITIO CALCULATION OF FORCE CONSTANTS AND EQUILIBRIUM GEOMETRIES IN POLYATOMIC MOLECULES. I. THEORY

17, 197 (1969) 2146

5 A. BERGNER, M. DOLG, W. KÜCHLE, H. STOLL, and H. PREUSS

AB INITIO ENERGY-ADJUSTED PSEUDOPOTENTIALS FOR ELEMENTS OF GROUPS 13-17

80, 1431 (1993) 1801

6 P. C. HARIHARAN and J. A. POPLE

ACCURACY OF AH EQUILIBRIUM GEOMETRIES BY SINGLE DETERMINANT MOLECULAR-ORBITAL THEORY

27, 209 (1974) 1559

7 S. MACURA and R. R. ERNST

ELUCIDATION OF CROSS RELAXATION IN LIQUIDS BY TWO-DIMENSIONAL NMR SPECTROSCOPY

41, 95 (1980) 1555

8 A. Z. PANAGIOTOPOULOS DIRECT DETERMINATION OF PHASE COEXISTENCE PROPERTIES OF FLUIDS BY MONTE-CARLO SIMULATION IN A NEW ENSEMBLE

61, 813 (1987) 1437

9 R. ENGLMAN and J. JORTNER

ENERGY GAP LAW FOR RADIATIONLESS TRANSITIONS IN LARGE MOLECULES

18, 145 (1970) 1416

10 W. F. VAN GUNSTEREN and H. J. C. BERENDSEN

ALGORITHMS FOR MACROMOLECULAR DYNAMICS AND CONSTRAINT DYNAMICS

34, 1311 (1977) 1335

11 S. NOSÉ and M. L. KLEIN CONSTANT PRESSURE MOLECULAR DYNAMICS FOR MOLECULAR SYSTEMS

50, 1055 (1983) 1156

12 B. J. ORR J. F. WARD PERTURBATION THEORY OF THE NON-LINEAR OPTICAL POLARIZATION OF AN ISOLATED SYSTEM

20, 513 (1971) 1128

13 A. D. McLACHLAN SELF-CONSISTENT FIELD THEORY OF THE ELECTRON SPIN DISTRIBUTION IN PI-ELECTRON RADICALS

3, 233 (1960) 1049

14 G. J. MARTYNA, M. E. TUCKERMAN, D. J. TOBIAS, and M. L. KLEIN

EXPLICIT REVERSIBLE INTEGRATORS FOR EXTENDED SYSTEMS DYNAMICS

87, 1117 (1996) 1024

15 R. J. BUENKER, S. D. PEYERIMHOFF, and W. BUTSCHER

APPLICABILITY OF MULTI-REFERENCE DOUBLE-EXCITATION CI (MRD-CI) METHOD TO THE CALCULATION OF ELECTRONIC WAVEFUNCTIONS AND COMPARISON WITH RELATED TECHNIQUES

35, 771 (1978) 1005

16 H. C. LONGUET-HIGGINS THE SYMMETRY GROUPS OF NON-RIGID MOLECULES 6, 445 (1963) 983 17 J. K. JOHNSON,

J. A. ZOLLWEG, and K. E. GUBBINS

THE LENNARD-JONES EQUATION OF STATE REVISITED 78, 591 (1993) 900

18 J. B. HAYTER and J. PENFOLD

AN ANALYTIC STRUCTURE FACTOR FOR MACROION SOLUTIONS

42, 109 (1981) 867

19 A. R. HOY, I. M. MILLS, and G. STREY

ANHARMONIC FORCE CONSTANT CALCULATIONS 24, 1265 (1972) 862

20 J. K. G. WATSON SIMPLIFICATION OF THE MOLECULAR VIBRATION-ROTATION HAMILTONIAN

15, 479 (1968) 841

21 A.Z. PANAGIOTOPOULOS, N. QUIRKE, M. STAPLETON, D. J. TILDESLEY

PHASE-EQUILIBRIA BY SIMULATION IN THE GIBBS ENSEMBLE: ALTERNATIVE DERIVATION, GENERALIZATION AND APPLICATION TO MIXTURE AND MEMBRANE EQUILIBRIA

63, 527 (1988) 830

22 N. C. HANDY and A. J. COHEN

LEFT-RIGHT CORRELATION ENERGY 99, 403 (2001) 823

23 D. E. STOGRYN and A. P. STOGRYN

MOLECULAR MULTIPOLE MOMENTS 11, 371 (1966) 785

24 W. G. CHAPMAN, G. JACKSON, and K. E. GUBBINS

PHASE-EQUILIBRIA OF ASSOCIATING FLUIDS: CHAIN MOLECULES WITH MULTIPLE BONDING SITES

65, 1057 (1988) 770

25 J. I. SIEPMANN and D. FRENKEL

CONFIGURATIONAL BIAS MONTE CARLO: A NEW SAMPLING SCHEME FOR FLEXIBLE CHAINS

75, 59 (1992) 751

26 J. A. POPLE and D. P. SANTRY

MOLECULAR ORBITAL THEORY OF NUCLEAR SPIN COUPLING CONSTANTS

8, 1 (1964) 740

27 A. J. STONE and M. ALDERTON

DISTRIBUTED MULTIPOLE ANALYSIS: METHODS AND APPLICATIONS

56, 1047 (1985) 706

28 J. J. NICOLAS, K. E. GUBBINS, W. B. STREETT, and D. J. TILDESLEY

EQUATION OF STATE FOR THE LENNARD-JONES FLUID 37, 1429 (1979) 673

29 C. K. JØRGENSEN and HYPERSENSITIVE PSEUDOQUADRUPOLE TRANSITIONS IN 8, 281 (1964) 656

B. R. JUDD LANTHANIDES 30 G. S. RUSHBROOKE and

P. J. WOOD ON THE CURIE POINTS AND HIGH TEMPERATURE SUSCEPTIBILITIES OF HEISENBERG MODEL FERROMAGNETICS

1, 257 (1958) 650

31 H. REHAGE and H. HOFFMANN

VISCOELASTIC SURFACTANT SOLUTIONS: MODEL SYSTEMS FOR RHEOLOGICAL RESEARCH

74, 933 (1991) 621

32 S. MELCHIONNA, G. CICCOTTI, and B. L. HOLIAN

HOOVER NPT DYNAMICS FOR SYSTEMS VARYING IN SHAPE AND SIZE

78, 533 (1993) 620

33 J.-P. HANSEN and J. B. HAYTER

A RESCALED MSA STRUCTURE FACTOR FOR DILUTE CHARGED COLLOIDAL DISPERSIONS

46, 651 (1982) 608

34 H. J. WERNER and W. MEYER

PNO-CI AND PNO-CEPA STUDIES OF ELECTRON CORRELATION EFFECTS: V. STATIC DIPOLE POLARIZABILITIES OF SMALL MOLECULES

31, 855 (1976) 601

35 J. A. BARKER, R. A. FISHER, and R. O. WATTS

LIQUID ARGON: MONTE CARLO AND MOLECULAR DYNAMICS CALCULATIONS

21, 657 (1971) 556

36 H. M. McCONNELL and J. STRATHDEE

THEORY OF ANISOTROPIC HYPERFINE INTERACTIONS IN PI-ELECTRON RADICALS

2, 129 (1959) 548

37 L. BLUM MEAN SPHERICAL MODEL FOR ASYMMETRIC ELECTROLYTES: I. METHOD OF SOLUTION

30, 1529 (1975) 538

38 W. L. JORGENSEN and J. D. MADURA

TEMPERATURE AND SIZE DEPENDENCE FOR MONTE-CARLO SIMULATIONS OF TIP4P WATER

56, 1381 (1985) 525

39 O. TAPIA and O. GOSCINSKI

SELF-CONSISTENT REACTION FIELD THEORY OF SOLVENT EFFECTS

29, 1653 (1975) 499

40 G. LIPPERT, J. HUTTER, and M. PARRINELLO

A HYBRID GAUSSIAN AND PLANE WAVE DENSITY FUNCTIONAL SCHEME

92, 477 (1997) 490

41 P. TARAZONA, U. MARINI BETTOLO MARCONI, and R. EVANS

PHASE EQUILIBRIA OF FLUID INTERFACES AND CONFINED FLUIDS: NON-LOCAL VERSUS LOCAL DENSITY FUNCTIONALS

60, 573 (1987) 489

42 H.-J. WERNER THIRD-ORDER MULTIREFERENCE PERTURBATION THEORY: THE CASPT3 METHOD

89, 645 (1996) 478

43 J. A. BARKER and R. O. WATTS

MONTE CARLO STUDIES OF THE DIELECTRIC PROPERTIES OF WATER-LIKE MODELS

26, 789 (1973) 477

44 R. EPPENGA and D. FRENKEL

MONTE CARLO STUDY OF THE ISOTROPIC AND NEMATIC PHASES OF INFINITELY THIN HARD PLATELETS

52, 1303 (1984) 471

45 D. C. FROST, A. ISHITANI, and C. A. McDOWELL

X-RAY PHOTOELECTRON SPECTROSCOPY OF COPPER COMPOUNDS

24, 861 (1972) 470

46 G. JACKSON, W. G. CHAPMAN, and K. E. GUBBINS

PHASE EQUILIBRIA OF ASSOCIATING FLUIDS: SPHERICAL MOLECULES WITH MULTIPLE BONDING SITES

65, 1 (1988) 456

47 B. T. PICKUP and O. GOSCINSKI

DIRECT CALCULATION OF IONIZATION ENERGIES: I. CLOSED SHELLS

26, 1013 (1973) 453

48 A. BERNING, M. SCHWEIZER, H.-J. WERNER, P. J. KNOWLES, and P. PALMIERI

SPIN-ORBITAL MATRIX ELEMENTS FOR INTERNALLY CONTRACTED MULTIREFERENCE CONFIGURATION INTERACTION WAVEFUNCTIONS

98, 1823 (2000) 447

49 A. SAMOSON, E. LIPPMAA, and A. PINES

HIGH RESOLUTION SOLID-STATE NMR AVERAGING OF SECOND-ORDER EFFECTS BY MEANS OF A DOUBLE-ROTOR

65, 1013 (1988) 442

50 P. PYYKKÖ SPECTROSCOPIC NUCLEAR QUADRUPOLE MOMENTS 99, 1617 (2001) 436 Table 2. Top 50 most cited papers published in Molecular Physics according to Web of Science © Thomson Reuters 2016 – Clarivate Analytics; citations to 16 October 2016.

The use of pseudopotentials (PP) that allow one to exclude the inactive electrons at atomic cores from explicit quantum-chemical calculations is now well established. A key benefit of such an approach is the large saving in computational effort both in terms of time and memory requirements. In addition, scalar relativistic effects can be incorporated in a straight forward and reliable manner by using this type of approach. In their Molecular Physics paper of 1993 (number 5 in Table 2), Bergner et al. describe the determination of

relativistic PP for elements of groups 13 through 17 of the periodic table. The procedure developed by this group involves the estimation of PP parameters from the valence energies of neutral and ionic atomic states. Scalar relativistic effects are now included routinely in quantum-mechanical calculations with the PP method in popular quantum-chemistry programs such as COLUMBUS, GAMESS, GAUSSIAN, MOLPRO, and TURBOMOLE.

Molecular spectroscopy, including nuclear magnetic resonance (NMR), has been a popular subject of research contributions throughout the history of the journal. In the case of two-dimensional 2D-NMR (pioneered by Ernest and co-workers in the 1970s), two frequencies are employed rather than one to provide additional information about the fine molecular structure; this is especially useful in the case of large molecules. In their paper published in Molecular Physics in 1980 (number 7 in Table 2), Macura and Ernst apply 2D-NMR to elucidate the cross-relaxation pathways in liquids and develop a theory for transient nuclear Overhauser effects. The research is particularly useful in studies of intra- and inter-molecular cross relaxation in macromolecular systems. Nuclear Overhauser effect spectroscopy (NOESY), which takes advantage of the transfer of nuclear spin polarization due to cross relaxation, is commonly used to characterize the detailed structure of large biomolecules such as proteins. Panagiotopoulos submitted his 1987 paper (number 8 in Table 2) on the now ubiquitous Gibbs-ensemble Monte Carlo (GEMC) simulation technique to Molecular Physics while he was a postdoctoral fellow with Rowlinson at the Physical Chemistry Laboratory (PCL) in Oxford; I had the pleasure of overlapping with him at the time as a final-year doctoral student at the PCL. Up until that point, the molecular simulation of fluid-phase equilibria had been studied either directly in the two-phase region by setting up a liquid film in contact with two vapour regions (employing the usual periodic boundary conditions) or by adopting the time-consuming procedure (particularly in the case of mixtures) of determining the chemical potential along an appropriate thermodynamic path to establish coexistence. The advent of the GEMC approach allowed for the molecular simulation of coupled phases at thermodynamic equilibrium without the presence of an interface; this naturally reduces the unwanted surface contribution to the properties which is otherwise present due system-size effects. The

enduring popularity of the GEMC approach stems from key advantages in its straight forward implementation to mixtures and other types of phase equilibria involving confined systems or membranes (see paper number 21 in Table 2).

Figure 2. Past Editors of Molecular Physics, David Buckingham (1968-1972), Joan van der Waals (1958-1963), and John Rowlinson (1967-1973), with George Jackson, the current chair of Editors.

A commemorative lunch was held at Exeter College Oxford on 29 April 2016 in order to acknowledge the invaluable contribution made by past Editors and Advisory Board members of Molecular Physics to the success of the journal (see Figure 1). This also presented us with the opportunity of a celebration in anticipation of John Rowlinson’s ninetieth birthday on 12 May 2016.

Figure 3. Molecular Physics Cake representing the Rowlinson (1951) model of water in commemoration of John Rowlinson’s 90th birthday.

John was joined by a number of our senior Editors, including David Buckingham, and

Joan van der Waals (see Figure 2), and presented with a cake to mark the event; the icing decoration of the cake (see Figure 3) was inspired by the force field for water, singlehandedly developed by John in 1951 as a young PhD student, which can be considered as one of the earliest precursors of the point-charge models (e.g., BNS, ST2, SPC, and TIPS) in widespread use in modern computer simulation. The first molecular simulations of the dielectric properties of water were described in a paper by Barker and Watts in 1973 (number 43 in Table 2) using the Rowlinson model, in which they introduced the reaction-field approach to treat the long-range nature of electrostatic interactions. The Editors of Molecular Physics are very grateful to the editorial team at our publishers Taylor and Francis Ltd. (Justin Robinson, Huw Price, Colin Bulpitt, and Richard Steele) for organizing the event and for their continued support of the journal, and to Lauren Harvey for acting as the photographer for the day. We are also very much indebted to Tim Softley for his tireless and faithful stewardship of the journal as Chair; after 13 years of service editing Molecular Physics he will be joining the Advisory Board. We wish him well in his future endeavours as Pro-Vice-Chancellor for Research and Knowledge Transfer at the University of Birmingham. George Jackson for the Editors Imperial College London