Halogenation of small alkanes; this one should be the most familiar because it is used in every organic chemistry course. Polymerization of ethylene to polyethylene at high pressure is an industrial reaction of some prominence.

Wouldn't most forms of chemical vapor deposition qualify?

There will still be lots of people whose expertise lies in the actual manipulation of atoms and molecules who will not accept a simulation. They will claim that simulations are based on approximations (which they generally are). It is rare that you find people who understand the theoretical & computational & experimental realms sufficiently that they can feel comfortable with what each realm is able to "prove".

You also leave out the cost issues. Even if you have a valid simulation and can invent a valid assembly path you still have the problem that if it costs too much to produce a usable concrete result then the effort is rather pointless. As Robert Freitas pointed out in his recent interview, "Each nanorobot design may require huge design teams of thousands of technical people" so one is talking something like $100M-$1B per nanorobot design (this may not include the cost of designing an assembly process or the cost of the components necessary to manufacture all of the parts contained in a nanorobot). Yes, I realize in the final analysis those costs get amortized over billions of people. But the gap between starting with nothing and that final level of justification is quite large.

Don't forget Robert Freitas, Chris Phoenix, Will Ware and others who have made significant contributions to the far sighted vision. And then there are probably several dozen who have contributed significantly from a nearer term perspective.

I don't think the MNT critics (pundits?) are being paid. I think they generally believe what they say. I think the major problem is that they have not taken the time to investigate the serious literature. This may be a typical situation for most people who have higher(?) positions. This was very clear at the NIH Nanomedicine Roadmap meeting in May 2004. I would be very surprised if more than 5% of an audience of 300-400 people (including several NIH Institute directors) had read either Nanosystems or any of the Nanomedicine volumes. That in large part is probably due to time constraints related to their job responsibilities.

It may also be the case as Christine Peterson suggested in the April 2004 letter to Foresight Inst. Senior Associates, "We believe we understand the motivation behind it — fear that discussion of MNT may somehow negatively impact shorter-term nanotech research, either by redirecting funds toward MNT or by reducing the total amount due to supposedly-negative public reaction to MNT." (Where the "it" being discussed is efforts by some groups/organizations to discourage research into or the promotion of subjects such as molecular manufacturing and/or nanorobots.)

The best way to silence the critics is to make a complete design for an MNT system and provide and open source simulation platform. The only argument that holds any weight is "how are we ever going to build that?" Providing a working simulation won't fix that but at least it will silence the critics who claim that a working system is not theoretically possible.

Why is this man Smalley so prideful and unable to just examine the data that men and women such as Robert Bradbury, Eric Drexler, Ralph Merkle, and Chris Peterson have provided, year after year? Is it his own pride that causes him to grasp at straws, as Robert pointed out, or, are there people behind him that have him as a paid debunker? What is this man's problem???

Thats a good point as well Chip. I am unsure if it occurs very much at familiar atmospheric levels (perhaps 0 to 7 miles) [Though perhaps pollutants like CO or NO might contribute]. But at higher altitudes where one has UV radiation as an energy source one certainly has an extensive variety of chemical reactions taking place. As the whole chlorofluorocarbon experience points out humans can contribute extensively to these processes without realizing it.

But going back to the original article it seems as if Smalley is stuck on the fact that the only "assemblers" can be the ribosome or a series of enzymes (such as those that assemble everything from cholesterol to B-12 to maitotoxin (one of the largest biological molecules). He feels that the ribosome or enzymes are necessary for nanotechnology. I could provide examples of solutions that answer many of his questions but to do a reasonable job would provide doing some research to cite references and that would be a bit longer than I'm willing something I'm willing to attempt this morning.

But his statements "Computer-controlled fingers will be too fat and too sticky to permit the requisite control. Fingers just can't do chemistry with the necessary finesse." and "it would be helpful to all of us who take the nanobot assembler idea of "Engines of Creation" seriously if you would tell us more about this nonaqueous enzymelike chemistry." seem to suggest that he read EoC and decided the entire concept was impossible and has never bothered to read Nanosystems or any papers on mechanosynthesis. He now appears to be grasping at straws to maintain his stated position.

Robert

…solvent effects can not occur in gas phase…

I think one has to be slightly careful here. A mixture of two or more real gases will display mole-fraction-dependent deviations from ideality, e.g. from Dalton's and Amagat's "laws". These are, if you like, "solvent effects". But because gas-phase reactions typically proceed by binary collision, one species does not directly affect a reaction between two others. I think that's what you meant.

> Are there any good examples of reactions where the
> reactants themselves form the gas

Halogenation of small alkanes; this one should be the most familiar because it is used in every organic chemistry course. Polymerization of ethylene to polyethylene at high pressure is an industrial reaction of some prominence.

> or is there a gas "solvent"?

No; solvent effects can not occur in gas phase because there are not enough molecules of such "solvent" and they are not close enough together.

> Now of course if the only use of the solvent is
> to allow rotation of the molecules into proper
> orientation and/or provide them with some net
> velocity when they encounter each other

The solvent actually hinders molecular movement, and thus is no help in orienting or acceleration molecules. It is however extremely important for stabilization of intermediates; water can very effectively stabilize charged ions and thus aids in dissociation of polar leaving groups.

> Now of course there are reactions where the
> solvent molecules may play a role in the
> reaction itself but then one must wonder in what
> fraction of reactions that are commonly used is this the case?

Quite a few, actually. Proton transfers from and to water molecules is very common; many reactions involving carbonyl groups, for instance, begin and/or end by protonation of the oxygen.

Isn't atmospheric chemistry a whole, like, field unto itself? And the atmosphere is mostly gas phase, right? Or is there some more specific flavor of chemical operations in question here and I'm just misunderstanding the point?

Good point. It would seem that in some (most?) cases the solvent primarily exists to allow molecular motion to bring the molecules into proper orientation to allow the reaction to occur. That would suggest that you could also perform the reactions in a gaseous state. Are there any good examples of reactions where the reactants themselves form the gas or there is a gas "solvent"?

Now of course if the only use of the solvent is to allow rotation of the molecules into proper orientation and/or provide them with some net velocity when they encounter each other (pressure) then it would seem to me that those qualities are unimportant when one considers mechanosynthesis because the orientation and applied pressure are controlled by the assembler itself.

Now of course there are reactions where the solvent molecules may play a role in the reaction itself but then one must wonder in what fraction of reactions that are commonly used is this the case?