Journal of Chemical Physics is proud to be celebrating its 80th year as the leading and most cited journal in chemical physics. The Journal has been at the forefront of the field since its inception in 1933. The 80th Anniversary Collection includes seminal papers on electronic structure methods, potential energy surfaces, transition states and reaction pathways, Monte Carlo and molecular dynamics simulation methods and applications, time-dependent methods in quantum dynamics, electron transfer reactions, advances in nuclear magnetic resonance methods, and spectroscopic methods and formalisms including multidimensional techniques with applications ranging from water to proteins. Going forward, the Journal will continue to publish Communications, Perspectives, Special Topic sections, and regular articles in core areas of chemical physics as well as emerging and multidisciplinary fields. The Journal covers the latest breakthroughs in theoretical methods and advanced experimental techniques in chemical physics relevant to studies of atoms, molecules, clusters, liquids, glasses, crystals, polymers, biological molecules and networks, surfaces, interfaces, and materials. Here are 80 articles that highlight the 80 years of outstanding work published in the Journal. Happy 80th Anniversary to The Journal of Chemical Physics!

There are several common conventions in use by the gravitational-wave community to describe the amplitude of sources and the sensitivity of detectors. These are frequently confused. We outline the merits of and differences between the various quantities used for parameterizing noise curves and characterizing gravitational-wave amplitudes. We conclude by producing plots that consistently compare different detectors. Similar figures can be generated on-line for general use at

Complex dielectric constants have been measured at frequencies from below 20 c/s to 5 mc/s over the temperature range −40° to −75°C in glycerol, −45° to −90° in propylene glycol, and −80° to −140° in n-propanol. The results for n-propanol are described by the Debye equation, but the values for the other two require a modified equation corresponding to a broader range of dispersion at higher frequencies. In all three liquids, evidence is found for a second dispersion region at still higher frequencies, which accounts for much of the difference between the radio frequency and optical dielectric constant. The relaxation times are quantitatively described over wide ranges by an empirical rate equation of a form which also fits viscosity data. The significance of the various results is discussed.

The global predominance of three clonal Toxoplasma gondii lineages suggests that they are endowed with an exceptional trait responsible for their current parasitism of nearly all warm-blooded vertebrates. Genetic polymorphism analyses indicate that these clonal lineages emerged within the last 10,000 years after a single genetic cross. Comparison with ancient strains (approximately 1 million years) suggests that the success of the clonal lineages resulted from the concurrent acquisition of direct oral infectivity. This key adaptation circumvented sexual recombination, simultaneously promoting transmission through successive hosts, hence leading to clonal expansion. Thus, changes in complex life cycles can occur rapidly and can profoundly influence pathogenicity.