An experimentalist, Z.H. Li from Fudan University, and a computationalist, (is that a word?) D.G. Truhlar from University of Minnesota published a paper in JACS, "Nanosolids, Slushes, and Nanoliquids: Characterization of Nanophases in Metal Clusters and Nanoparticles". The basic idea is transferring the concept of a melting point (well, range) from the bulk scale to the nanoscale.
They did so by studying aluminum clusters, Aln, where n is 10-300. Before I get into their findings, a quote: "For convenience we call the particles with a diameter less than ~1 nm clusters and those with diameters larger than ~1
nm nanoparticles." These are just arbitrary definitions, and it's good to define things like this, to be more specific for the rest of the paper. However, I can't decide if this seems backwards to me. While nanoparticles should be on the scale of nanometers, I always think of clusters as being larger. Do I have this backwards in my mind?
There's a lot of discussion in the paper about the computational aspect, but since I have zero background in computational chemistry, I'm going to skip over this completely, so look into it yourself if that's your thing. They start off by saying, "For the particle sizes studied here, most atoms need to be classified as surface atoms rather than as interior atoms with bulk properties characteristic of a macroscopic particle", which sounds necessary, but I question it's accuracy as n approaches 300 in their study.
Phase isn't as well defined as you approach the nanoscale; changes in heat capacity can be due to changes on the atomic level, such as changes in equilibrium of isomers, so that can't be used as a strict measure, as it often is on the bulk scale. This is a point that's repeated several times, that phase become more ambiguous at this scale, and it's difficult or impossible to determine some of these measurements experimentally. However, I'm sure that it's possible to determine phase at this level, just not with the methods that we traditionally use.
The nomenclature
The title has the words nanosolids, nanoliquids, nanophases, and nanoparticles in it. I've already discussed the overuse of the prefix nano-, but if they've taken it this far, why couldn't they just use the term nanoslush? That's a much more entertaining image to me.
Speaking of nanostuff, there was another ASAP paper that uses the word nanowheels.
The layout
Normally, I'm a big fan of the JACS layout, in that they use footnotes, rather than endnotes, but I think they need to be more flexible about this. When they see how a final paper looks, they should change it to endnotes if need be. Why would they need to do this? Look at the 3rd page of this paper:
More than 50% of this page (all of the stuff in red) is devoted to showing references, and that is just unnecessary. This is a 14 page article, and seemingly a good chunk of that is due to references.
Slurpee image: Jonas Rask Design
Zhen Hua Li, Donald G. Truhlar (2008). Nanosolids, Slushes, and Nanoliquids: Characterization of Nanophases in Metal Clusters and Nanoparticles Journal of the American Chemical Society DOI: 10.1021/ja802389d
Godspeed.
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