In Memoriam
David Chandler
Bruce H. Mahan Professor of Chemistry, Emeritus
Professor of the Graduate School
UC Berkeley
1945-2017
Born October 15, 1945, in New York, N.Y., David Chandler passed away at home on April 18, 2017, after a heroic 20-year battle with cancer. His life was well-lived, and his scientific career was extraordinary. David is survived by his wife Elaine, along with their daughter Phoebe Chandler, her partner Sue Elderkin, and grandchildren Matthew and Mya Elderkin; and daughter Cynthia Chandler, her husband D. Bud Sperman, and grandchildren Sophia and Lilah Sperman. His intellectual family is expansive, including trainees who now occupy faculty positions across the world. This large group of scientists, profoundly influenced by his mentorship and friendship, comprises many scientists of distinction, and many who are on their way to being so.
David established himself early on as a standard-bearer in the discipline of statistical mechanics, which addresses the fundamentally inconstant nature of our world at the atomic scale. He demonstrated over and over again the power of statistical physics to reveal the essential workings of complex molecular systems. His extensive accomplishments in applying its principles, advancing its physical underpinnings, and innovating methods of analysis and computer simulation address a range of molecular phenomena that marks the modern frontiers of physical chemistry — from the glass transition to biomolecular assembly, from electron transfer in solution to the hydrophobic effect, from the microscopic dynamics of acid-base chemistry to the collective dynamics of water at electrodes. David’s work invigorated research in these diverse areas, injecting many key ideas and techniques, and held it to exacting standards that were both treasured and feared.
The magnitude of David’s scientific achievements is clear from the influence of his research — papers cited thousands of times decade after decade — evidence of the creativity, longevity, and impact of his work. These achievements were of course recognized by his peers. David, among his many accolades, was both a member of the National Academy of Sciences and a Foreign Member of the Royal Society. Such objective measures indicate David’s significance and distinction, but they do not alone paint an accurate portrait of a man whose life was inseparable from his science.
Together with Hans Andersen and John Weeks, David produced the WCA theory in 1971 (named after their last initials), which soon became the standard theory of the liquid state. Beyond the enormous success of this work, the bond that formed between them stands out, of which David remarked in his “Autobiography of David Chandler” in J. Phys. Chem B 2005, 109, 6459-6464: “The ties I made [with them] during this time are everlasting. They are my brothers in science and in spirit. We have faithfully supported one another for more than three decades.” This quote highlights how David saw science and humanity intertwined, and the way in which he cultivated the ties of friendship with his close collaborators. Conversely, bonds of friendship and family nourished David’s scientific life. Most notably, his wife Elaine, a physicist, served throughout his career as a critical collaborator and consultant, pushing him to communicate clearly, to reason carefully, and to employ the most sophisticated mathematical and computational tools available. His reputation as an unrivaled expert in these very skills testifies to the depth of Elaine’s influence. Indeed, Elaine did notable work of her own on rotating superfluids during her Ph.D. in physics with Gordon Baym at the University of Illinois.
A constant in David’s work was the search for connections between problems in diverse areas of science and the use of statistical mechanics as the conceptual and methodological framework with which to address them. This synthetic approach is a signature of the school of thought he built at Berkeley, whose basic perspective is articulated in his “little green book”, Introduction to Modern Statistical Mechanics (1987). This academic best seller became the standard introductory text in statistical mechanics for a generation of physical scientists. By all accounts, David was an outstanding teacher, both in writing and in front of a class.
A second notable effort towards creating a community of thought was establishing the Berkeley Mini Stat Mech Meeting. These yearly meetings are unique in style, covering broad topics in chemistry, physics, biology, and beyond, with statistical mechanics as a common theme. They aim to bring down the barriers between disciplines, and have been instrumental in fostering a sense of common purpose among those who adhere to the way David thought about science.
Beginning with his Ph.D. work at Harvard University (and building on his undergraduate training at the Massachusetts Institute of Technology), David’s scholarship focused initially, and very successfully, on the microscopic structure and thermodynamics of liquids. This timely but challenging subject had been deemed intractable by even legendary physicists like Lev Landau. The principles and intuition he developed in constructing WCA theory served as touchstones as his curiosity wandered more and more broadly across the reaches of physical chemistry. Developing a theory for the hydrophobic effect with the same power as WCA was a career-long goal for David, one that he ultimately achieved by synthesizing methods and concepts from the statistical mechanics of linear response and phase equilibrium. This theory emphasizes distinct mechanisms of hydrophobe solvation on small (a few Å) and large (>1 nm) length scales. The hydrophobic entities of greatest modern interest are constituents of biological molecules, e.g., nonpolar amino-acid side-chains and phospholipids’ greasy tail groups, whose typical size lies precisely at the crossover length scale he identified. Implications for biomolecular solubility, structure, and assembly are profound and far-reaching.
The low rates of chemical reactions, relative to frequencies of basic molecular motion, drew David’s interest throughout his career. In very small systems this slowness arises transparently from the topography of potential energy surfaces. Complex systems of modern interest, however, navigate diverse pathways from reactants to products, and their dynamical bottlenecks occur in a high-dimensional phase space that cannot be directly visualized or exhaustively surveyed. David’s key recognition is that slowness in this case is best understood as a feature not of standard configurational ensembles, but instead of ensembles comprising trajectories. The separation of time scales intrinsic to barrier crossing begets a rareness in this trajectory space — from the distribution of short equilibrium trajectories, only a tiny fraction exhibit reactivity. From this perspective he invented methods for sampling and quantifying reactive dynamics that revolutionized theoretical work on chemical kinetics. The most sophisticated of these methods, transition path sampling, allows for the sampling of barrier-crossing trajectories without a priori mechanistic understanding. It opened doors to studying kinetic processes that were previously approachable only through dangerously uncontrolled approximations. It also ushered in a new way of thinking about the statistical dynamics of molecular systems in general. This perspective emphasizes complexity in the space of trajectories that may not be reflected in static structure.
David proposed that vitrification of a liquid is the epitome of such dynamical complexity. Previously dominant theoretical perspectives were focused on structural changes, but experimental measurements in the early 2000s revealed that relaxation in glass formers displayed strong spatial fluctuations. This dynamical heterogeneity indicated that glassy dynamics was fluctuation dominated in a manner that could not be anticipated from thermodynamic considerations alone. Realizing that this behavior could be explained by effective constraints on dynamics, David and his coworkers developed what is known as the dynamic facilitation (DF) theory of the glass transition. A prediction of the DF approach is that the characteristic super-Arrhenius growth of the relaxation time or the viscosity of supercooled liquids grows as the exponential of a parabola of the inverse temperature. Extensive studies confirmed the validity of this “parabolic law”, showing it can account in a universal manner for all available experimental data.
David's interests in solvation and rare events intersected in a series of contributions to electron transfer theory that illuminated the molecular details underpinning successful phenomenological treatments. This area clearly demonstrated David's ability to see connections between seemingly disparate theoretical works and translate those connections into deep physical insight. In particular, this work established two principles that continue to guide researchers’ perspectives on the topic. The first was that quantum theory of solvation is isomorphic with the classical theory of solvation with additional fluctuating degrees of freedom. While this perspective has its roots in Feynman’s path integral formulation of quantum mechanics, David shaped it into an elegant and practical way to solve otherwise intractable computational challenges. This quantum-classical isomorphism allowed one to use the full arsenal of classical statistical mechanics to study solvated electrons and their motions. The second principle was that electric field fluctuations within the liquid state, as the sum of many weakly correlated components, ought to be Gaussian distributed. This principle simultaneously informed the theory of dielectrics and the theory of the hydrophobic effect, and when it broke down, signaled the emergence of collective phenomena. At extended interfaces, such collective fluctuations can profoundly influence mechanisms of energy storage, as David demonstrated in super capacitors and electrochemistry.
One of the greatest sources of enjoyment for David away from science was tennis, which he played avidly throughout his life. As a student, David obtain high rankings in collegiate tennis and a notable mention in a United States Tennis Association listing. One of his most cherished accomplishments was being quickly admitted into the Berkeley Tennis Club, where later in life he would compete in sponsored seniors' tennis tournaments. David was also a talented pianist, and favored jazz to classical pieces. He was an avid art collector, and owned several Rembrandts and Whistlers and also excellent examples of twentieth-century art, including works by Picasso and Matisse.
David joined the faculty of the University of California, Berkeley, in 1986, when he was recruited away from a tenured position at the University of Pennsylvania (which had in turn recruited him away from the University of Illinois, where he had advanced from assistant professor to full professor). In the late 1990s, David was active in departmental leadership at Berkeley, serving as the chair of the Department of Chemistry’s planning committee for two years. He was particularly proud of the role he played in recruiting Graham Fleming, a future vice chancellor of research, and fellow member of the National Academy of Science. At that time, David also led the department in revamping the undergraduate physical chemistry courses, establishing a model emulated across the country. David also served on the advisory board for the Miller Institute from 2002 to 2008, acting as executive director from 2006 to 2008. He retired from his faculty appointment in 2015, but remained scientifically active as a Professor of the Graduate School, producing important results and serving as a mentor to students, postdocs, and colleagues until the very final weeks of his life.
Phillip Geissler
Juan Garrahan
David Limmer
2019
David established himself early on as a standard-bearer in the discipline of statistical mechanics, which addresses the fundamentally inconstant nature of our world at the atomic scale. He demonstrated over and over again the power of statistical physics to reveal the essential workings of complex molecular systems. His extensive accomplishments in applying its principles, advancing its physical underpinnings, and innovating methods of analysis and computer simulation address a range of molecular phenomena that marks the modern frontiers of physical chemistry — from the glass transition to biomolecular assembly, from electron transfer in solution to the hydrophobic effect, from the microscopic dynamics of acid-base chemistry to the collective dynamics of water at electrodes. David’s work invigorated research in these diverse areas, injecting many key ideas and techniques, and held it to exacting standards that were both treasured and feared.
The magnitude of David’s scientific achievements is clear from the influence of his research — papers cited thousands of times decade after decade — evidence of the creativity, longevity, and impact of his work. These achievements were of course recognized by his peers. David, among his many accolades, was both a member of the National Academy of Sciences and a Foreign Member of the Royal Society. Such objective measures indicate David’s significance and distinction, but they do not alone paint an accurate portrait of a man whose life was inseparable from his science.
Together with Hans Andersen and John Weeks, David produced the WCA theory in 1971 (named after their last initials), which soon became the standard theory of the liquid state. Beyond the enormous success of this work, the bond that formed between them stands out, of which David remarked in his “Autobiography of David Chandler” in J. Phys. Chem B 2005, 109, 6459-6464: “The ties I made [with them] during this time are everlasting. They are my brothers in science and in spirit. We have faithfully supported one another for more than three decades.” This quote highlights how David saw science and humanity intertwined, and the way in which he cultivated the ties of friendship with his close collaborators. Conversely, bonds of friendship and family nourished David’s scientific life. Most notably, his wife Elaine, a physicist, served throughout his career as a critical collaborator and consultant, pushing him to communicate clearly, to reason carefully, and to employ the most sophisticated mathematical and computational tools available. His reputation as an unrivaled expert in these very skills testifies to the depth of Elaine’s influence. Indeed, Elaine did notable work of her own on rotating superfluids during her Ph.D. in physics with Gordon Baym at the University of Illinois.
A constant in David’s work was the search for connections between problems in diverse areas of science and the use of statistical mechanics as the conceptual and methodological framework with which to address them. This synthetic approach is a signature of the school of thought he built at Berkeley, whose basic perspective is articulated in his “little green book”, Introduction to Modern Statistical Mechanics (1987). This academic best seller became the standard introductory text in statistical mechanics for a generation of physical scientists. By all accounts, David was an outstanding teacher, both in writing and in front of a class.
A second notable effort towards creating a community of thought was establishing the Berkeley Mini Stat Mech Meeting. These yearly meetings are unique in style, covering broad topics in chemistry, physics, biology, and beyond, with statistical mechanics as a common theme. They aim to bring down the barriers between disciplines, and have been instrumental in fostering a sense of common purpose among those who adhere to the way David thought about science.
Beginning with his Ph.D. work at Harvard University (and building on his undergraduate training at the Massachusetts Institute of Technology), David’s scholarship focused initially, and very successfully, on the microscopic structure and thermodynamics of liquids. This timely but challenging subject had been deemed intractable by even legendary physicists like Lev Landau. The principles and intuition he developed in constructing WCA theory served as touchstones as his curiosity wandered more and more broadly across the reaches of physical chemistry. Developing a theory for the hydrophobic effect with the same power as WCA was a career-long goal for David, one that he ultimately achieved by synthesizing methods and concepts from the statistical mechanics of linear response and phase equilibrium. This theory emphasizes distinct mechanisms of hydrophobe solvation on small (a few Å) and large (>1 nm) length scales. The hydrophobic entities of greatest modern interest are constituents of biological molecules, e.g., nonpolar amino-acid side-chains and phospholipids’ greasy tail groups, whose typical size lies precisely at the crossover length scale he identified. Implications for biomolecular solubility, structure, and assembly are profound and far-reaching.
The low rates of chemical reactions, relative to frequencies of basic molecular motion, drew David’s interest throughout his career. In very small systems this slowness arises transparently from the topography of potential energy surfaces. Complex systems of modern interest, however, navigate diverse pathways from reactants to products, and their dynamical bottlenecks occur in a high-dimensional phase space that cannot be directly visualized or exhaustively surveyed. David’s key recognition is that slowness in this case is best understood as a feature not of standard configurational ensembles, but instead of ensembles comprising trajectories. The separation of time scales intrinsic to barrier crossing begets a rareness in this trajectory space — from the distribution of short equilibrium trajectories, only a tiny fraction exhibit reactivity. From this perspective he invented methods for sampling and quantifying reactive dynamics that revolutionized theoretical work on chemical kinetics. The most sophisticated of these methods, transition path sampling, allows for the sampling of barrier-crossing trajectories without a priori mechanistic understanding. It opened doors to studying kinetic processes that were previously approachable only through dangerously uncontrolled approximations. It also ushered in a new way of thinking about the statistical dynamics of molecular systems in general. This perspective emphasizes complexity in the space of trajectories that may not be reflected in static structure.
David proposed that vitrification of a liquid is the epitome of such dynamical complexity. Previously dominant theoretical perspectives were focused on structural changes, but experimental measurements in the early 2000s revealed that relaxation in glass formers displayed strong spatial fluctuations. This dynamical heterogeneity indicated that glassy dynamics was fluctuation dominated in a manner that could not be anticipated from thermodynamic considerations alone. Realizing that this behavior could be explained by effective constraints on dynamics, David and his coworkers developed what is known as the dynamic facilitation (DF) theory of the glass transition. A prediction of the DF approach is that the characteristic super-Arrhenius growth of the relaxation time or the viscosity of supercooled liquids grows as the exponential of a parabola of the inverse temperature. Extensive studies confirmed the validity of this “parabolic law”, showing it can account in a universal manner for all available experimental data.
David's interests in solvation and rare events intersected in a series of contributions to electron transfer theory that illuminated the molecular details underpinning successful phenomenological treatments. This area clearly demonstrated David's ability to see connections between seemingly disparate theoretical works and translate those connections into deep physical insight. In particular, this work established two principles that continue to guide researchers’ perspectives on the topic. The first was that quantum theory of solvation is isomorphic with the classical theory of solvation with additional fluctuating degrees of freedom. While this perspective has its roots in Feynman’s path integral formulation of quantum mechanics, David shaped it into an elegant and practical way to solve otherwise intractable computational challenges. This quantum-classical isomorphism allowed one to use the full arsenal of classical statistical mechanics to study solvated electrons and their motions. The second principle was that electric field fluctuations within the liquid state, as the sum of many weakly correlated components, ought to be Gaussian distributed. This principle simultaneously informed the theory of dielectrics and the theory of the hydrophobic effect, and when it broke down, signaled the emergence of collective phenomena. At extended interfaces, such collective fluctuations can profoundly influence mechanisms of energy storage, as David demonstrated in super capacitors and electrochemistry.
One of the greatest sources of enjoyment for David away from science was tennis, which he played avidly throughout his life. As a student, David obtain high rankings in collegiate tennis and a notable mention in a United States Tennis Association listing. One of his most cherished accomplishments was being quickly admitted into the Berkeley Tennis Club, where later in life he would compete in sponsored seniors' tennis tournaments. David was also a talented pianist, and favored jazz to classical pieces. He was an avid art collector, and owned several Rembrandts and Whistlers and also excellent examples of twentieth-century art, including works by Picasso and Matisse.
David joined the faculty of the University of California, Berkeley, in 1986, when he was recruited away from a tenured position at the University of Pennsylvania (which had in turn recruited him away from the University of Illinois, where he had advanced from assistant professor to full professor). In the late 1990s, David was active in departmental leadership at Berkeley, serving as the chair of the Department of Chemistry’s planning committee for two years. He was particularly proud of the role he played in recruiting Graham Fleming, a future vice chancellor of research, and fellow member of the National Academy of Science. At that time, David also led the department in revamping the undergraduate physical chemistry courses, establishing a model emulated across the country. David also served on the advisory board for the Miller Institute from 2002 to 2008, acting as executive director from 2006 to 2008. He retired from his faculty appointment in 2015, but remained scientifically active as a Professor of the Graduate School, producing important results and serving as a mentor to students, postdocs, and colleagues until the very final weeks of his life.
Phillip Geissler
Juan Garrahan
David Limmer
2019
