A publication of the Foresight Institute
As a result of the U.S. budget wrangling last fall, government
funding for research rose some twelve percent overall. Both
Congress and the President seem to believe, vaguely, that
research is good. Congress sees industrial technology as the key
to improving America's industrial competitiveness. It has boosted
funding for a wide range of "critical" or
"pre-competitive" technologies. Congress is also
contemplating a change to the research and experimentation tax
credit which could encourage more research by private companies.
Meanwhile, President Bush has concentrated his efforts on a few
specific initiatives, such as high-performance computing. [Nature,
348:97, 8Nov90; Science, p747,
The bad news may be the way in which that money is being spent. According to Nature [347:697, 25Oct90], NASA will receive some $13.9 billion this year, half the Federal research budget. The National Science Foundation, by contrast, will get only about $2.4 billion, roughly the cost of NASA's newest Space Shuttle. Even ardent fans of manned spaceflight may question these priorities, considering the potential of new technologies for extending human capabilities in space and elsewhere.
There's worse news in the method by which research money is now being allocated: In the past, the science establishment worked out a unified program each year and collectively lobbied Congress for funding. Last year, however, a group of dissident biologists split from the pack and hired their own lobbyist. [Nature 348:270, 22Nov90] This is a dangerous precedent. If other groups follow the biologists' lead, Congress may begin distributing research funds on the basis of political pull, rather than scientific merit (as perceived by the science establishment). At best, this would mean worthy projects would not be funded. At worst, scarce research money would be directed to projects which could not possibly succeed.
The current budget contains at least one such project, pork-barrelled by Senator Ted Stevens (R-Alaska). Senator Stevens arranged a $34 million grant for the University of Alaska to "harness the electrojet" as a source of electrical power. The electrojet is an electric current high in the ionosphere, related to the aurora borealis; tapping it for power is about as practical as feeding lightning into the power grid. The recipients of the grant, knowing it to be scientifically unsound, managed to develop an elaborate rationalization which allowed them to accept the money anyway [Nature, 348:101, 8Nov90]. Of course, $34 million would go a long way toward developing nanotechnology.
The Commission of European Communities has decided to join Japan's Human Frontier Science Program (HFSP). HFSP is the Japanese government's leading international research program, although international financial participation has been slow to materialize. This new agreement means that smaller European countries, outside the "G7" group of nations, will be able to take part in the program. Several U.S. researchers have received HFSP grants, but the U.S. government still views HFSP with a certain amount of suspicion. Among other goals, HFSP is investigating aspects of biochemistry and molecular assembly, a possible path to molecular machinery. [Nature, 347:413, 4Oct90]
Two Englishmen have created a computer-based system for extracting better decisions from a group of experts. The computer asks the group a series of questions related to the decision, and each individual enters his opinions on a numeric keypad. The computer weights and tabulates the responses and displays the combined result. So far, this is a standard technique from decision analysis. But the computer also displays histograms of the input data. This allows a moderator to isolate areas of disagreement and investigate them further. One individual may have an insight which others lack; the moderator can spot such discrepancies on the histogram, and ask the stray to explain his reasoning. From such debate can emerge a new consensus. In theory, this happens at every committee meeting, but the new software is much more effective in practice than the usual meeting. The new system, called Teamworker, appears to be a genuine advance in complex decision-making [Science, 250:367, 19Oct90].
Japan, meanwhile, is attempting to automate the ways in which scientists exchange information. The new National Academic Center for Science Information Systems (NACSIS) includes technical and bibliographic databases and electronic mail services. The system designers are paying particular attention to the users' needs for communication. Some such tools are available in the U.S., but only as a haphazard collection of parts designed for other uses [Nature, 347:561, 11Oct90].
The Japan Technology Transfer Association (JTTAS) is setting up a research project into new computing technologies, including neural and biological computing. This project, called the International Institute of Novel Computing (IINC), is distinct from the nascent "sixth-generation computer" project proposed by Japan's well-known MITI (Ministry of International Trade and Industry). JTTAS gets its funding largely from private sources and says the two computer projects are complementary [Nature, 347:217, 20Sep90].
MITI recently announced that it would spend some $171 million over the next ten years to study "microtechnology." This term refers to miniature machines created by bulk technology, not to molecular manufacturing, but in Japan these techniques are seen as complementary. Germany is planning to devote some $255 million over four years to similar research. The National Science Foundation in the U.S. is supporting such research at a level of $2 million a year. [Seattle Times, 7Sep90]
A recent paper by three Japanese researchers described a reversible three-state photoelectrochemical reaction which might be used to make extremely dense computer memories [Nature, 347:658, 18Oct90]. The researchers' affiliation is intriguing: Department of Synthetic Chemistry, Faculty of Engineering, University of Tokyo. In the U.S., synthetic chemists insist on being described as pure scientists, despite their role in designing and building molecular objects not found in nature. Molecular engineering will progress faster when those who do it feel as comfortable with the label "engineer" as do the synthetic chemists at the University of Tokyo.
Stewart Cobb is an aerospace engineer and was an early member of the MIT Nanotechnology Study Group.
Research in nanotechnology continues to grow: the latest indicator is the recent interest in computational nanotechnology here at the Xerox Palo Alto Research Center. In December we bought a Silicon Graphics 4D/35 workstation (6 megaflops) and the Polygraf molecular modeling software from BioDesign. This lets us model chemically stable structures with as many as 20,000 atoms, including proposed bearings, mechanical molecular logic elements, molecular structural elements, etc. In the future we expect to get software that will model transition states and reactive structures. Such quantum-mechanical techniques are far more computationally intensive, restricting analysis to ten or twenty atoms, but providing greater accuracy.
There is an accelerating trend towards modeling new designs
and new concepts on the computer before building them. GM has
found that "computational car crashes" on a CRAY are
cheaper, more flexible, and provide more information than real
car crashes. Pharmaceutical companies are investing heavily in
molecular modeling to investigate new drugs for similar reasons.
Xerox, at several different sites within the company and for
diverse reasons, is also pursuing this trend by modeling a range
of chemical systems.
Seen against this backdrop, work in computational nanotechnology (at PARC or anywhere else) is simply a continuation of the trend: before you build a car, a copier, or an assembler, you should first model it on a computer. This lets you review more designs more quickly and more cheaply before actually building (expensive) physical systems; it reduces the lag time from product conception to product delivery; and it improves the quality of the final product.
While it's not entirely clear how long it will be until we achieve a flexible molecular manufacturing capability, it *is* clear that we will get there more quickly and with fewer false starts if we model the components of such a system on a computer before actually building them.
Oversimplifying somewhat, there are two classes of molecular
modeling software: molecular mechanics systems and quantum
mechanical systems. Molecular mechanics usually treats the nuclei
of atoms as classical Newtonian point masses moving in a
potential energy function (or conservative force field) defined
by the electron cloud around them. There is no attempt to
determine where the electrons actually are, or even to worry
about the electrons at all. Rather, the positions of the nuclei
directly define the forces acting between them.
As an example, consider two hydrogen atoms bonded together to form a molecule. As the nuclei move closer together, they repel each other. As they move farther apart, they attract each other. In equilibrium, the two nuclei will stay at a characteristic distance. While this repulsion and attraction is actually the result of a complex quantum mechanical interaction, it can be summarized simply by noting the attractive or repulsive force acting between the two hydrogen nuclei as a function of their distance. A complex quantum mechanical interaction can be accurately summarized by a simple graph. We don't know the actual electron distribution that produced the forces acting on the two nuclei, and we don't care.
This is known more formally as the Born-Oppenheimer approximation: the nuclei swim in a sea of electrons, but if all we are concerned about is the positions of the nuclei, then we don't actually care where the electrons are: all we really care about is the force field acting between the nuclei. The electrons disappear from the computation and from our thinking, and are replaced by the force field.
The Polygraf software from BioDesign uses the Born-Oppenheimer approximation to greatly simplify the problem of modeling the interactions between nuclei. By using structural data, heats of formation, and vibrational frequencies determined experimentally for many different compounds, it is possible to deduce a fairly accurate representation of the force field that must be acting between the nuclei. A carbon-carbon bond prefers to be a certain length, while two hydrogens bonded to a single carbon have a certain preferred angle between them. These and other similar interactions form the building blocks of the force field. Once this field is known, any structure can be modeled (with greater or lesser accuracy), whether or not it was already known experimentally.
Empirically derived force fields have been available for many years. The better ones provide quite good results within the broad range of compounds they were designed to handle. By using this method, the geometry and interactions of chemically stable structures (rods within a matrix, a molecular bearing on a molecular shaft) can be modeled quite accurately.
This method has the great strength that a direct solution of Schrödinger's wave equation is not required. The empirically derived force field is used in its stead. It is this which allows modeling of structures with tens of thousands of atoms and more.
Of course, because the force field is based on data derived from chemically stable structures it does not provide information about unstable structures or transition states. For this, it is usual to compute an approximate solution to Schrödinger's equation (including the electronic structure). This requires more computational effort, but allows analysis of chemically unstable species (e.g., free radicals) and transition states where bonds are in the process of being made or broken.
Taken together, these two methods from computational chemistry can model the mechanical interactions of large structures with tens of thousands of atoms, and the chemical interactions of one or two dozen atoms when bonds are being made and broken. These are precisely the interactions that must be understood if we are to build complex structures with atomic precision. As we apply the methods of computational chemistry, a more detailed picture of molecular manufacturing will emerge: a picture that will shorten the path from today's limited abilities to the more general abilities of the future.
Dr. Merkle's interests range from neurophysiology to computer security; he is a researcher at Xerox Palo Alto Research Center.
A position will open in April 1991 for a Research Associate to conduct theoretical research in molecular nanotechnology. This position reports to K. Eric Drexler and is funded through a grant from a newly-formed research institute in molecular engineering.
Candidates must have a good grounding in physics, some substantial familiarity with chemistry, and an interest in applying these to molecular engineering. Writing skills and experience using computers are also required. Due to the multidisciplinary nature of this work, an ability to learn quickly through independent study is essential.
The successful candidate will have some characteristics in common with those of the "ideal" candidate, as follows:
The Research Associate position should be viewed as somewhat similar to that of a graduate student; compensation comes in two forms:
We anticipate that someone who does well in this position will eventually become an independent researcher, establishing his or her own reputation as one of the first professionals to move into this emerging field.
Interested applicants should forward one or more of the
following: resume, c.v., copies of published or unpublished
Mail to: K. Eric Drexler, Foresight Institute, P.O. Box 61058, Palo Alto, CA 94306 USA
The Palo Alto chapter of the Computer Professionals for Social Responsibility has recently formed a special interest group to explore new technical developments, social consequences, and potential benefits and dangers of nanotechnology. Founded by Apple computer scientist Ted Kaehler, a long-time participant in both CPSR and the Foresight Institute, the group meets every two weeks to discuss all aspects of the anticipated technology: implementation methods, applications, and eventual effects on our lives. The group will soon visit a local vendor of scanning tunneling and atomic force microscopes. For more information contact Ted at 408-974-6241 or email@example.com. Meeting notices are sent to members of the Palo Alto chapter of CPSR (you need not be a computer professional to join), or can be obtained electronically from Ted. CPSR can be reached at P.O. Box 717, Palo Alto, CA 94301.
In February Eric Drexler
gave a plenary lecture on nanotechnology, titled "Toward 1015
MIPS" at the IEEE's Compcon computer conference held in San
Francisco, and later spoke on "Freedom of the Press for the
Press of the Future." A proceedings volume (including the
latter paper but not the plenary lecture) is available from IEEE
Computer Society Press, 10662 Los Vaqueros Circle, PO Box 3014,
Los Alamitos, CA 90720-1264; request order number 2134.
Earlier in February he presented the concept to the New Roles in Society group at the American Association of Retired Persons, which has stimulated an invitation to speak at an April meeting of this group's steering committee. In January the MIT Nanotechnology Study Group held an event at which a videotape on nanotechnology was shown -- recorded at the Microelectronics and Computer Technology Corporation (MCC) -- followed by a telephone-linked question and discussion session.
In February, Ralph Merkle of the Computational Nanotechnology Project at Xerox Palo Alto Research Center spoke on nanotechnology at the Beckman Institute at the California Institute of Technology, and at University of Nevada at Las Vegas. The latter talk was sponsored by the American Chemical Society chapter and the local office of the Environmental Protection Agency.
Also in February, Dr. Merkle spoke on the same topic at the Xerox Research Center of Canada. In earlier months, he gave a well-received talk on silicon nanotechnology at the Frontiers of Supercomputing II meeting at Los Alamos, followed by a special evening session held on the topic.
From Foresight Update 11, originally published 15 March 1991.