It’s the name of this blog. But why?
Well, in Web2.0-land, a blog (can you hear my teeth grinding?) is quintessentially a space for the reciprocation of views, the exchange of ideas.
So far, so good, but the title is also a rather cheesy crystallographic pun because reciprocal space is a real thing. Well, actually it’s a weird, imaginary thing, a mathematical construct used by X-ray crystallographers to interpret the diffraction patterns of spots that we record from our crystals. In the crystal, the molecules are arranged in orderly rows and columns, stacked like bricks in unit cells. The orderliness is the key to strong scattering of the X-rays in the directions allowed by a mathematical rule known as Bragg’s Law.
But if you follow the maths—that damnable white rabbit—it takes you down a hole and before you know it you are in reciprocal space, where it is the spots of the diffraction pattern that are arrayed in rows and columns. But all the dimensions and angles are inverted – reciprocated. Crystals with small molecules packed into small unit cells create a huge reciprocal lattice where the spots are widely separated.
And, oddly enough, that’s where the book discussed in this week’s Fiction Lab comes in. As has been mentioned elsewhere, on Wednesday evening I railed against the scientific inanities of the plot of “As she crawled across the table”, a novel based on the creation, in a basement physics lab, of a portal into a parallel universe that wholly absorbed — metaphorically and sometimes literally — those who gazed into it. It was a very strange story. I hated it and yet, though I almost dare not admit it, there is a kind of resonance with my own fascination with reciprocal space.
As a protein crystallographer I make occasional visits to reciprocal space, usually to take a look at a strange entity that lurks there known as the Ewald Sphere. It’s an absorbing place. But if you make the effort to get acquainted, to get to know the angles and the curves, it will ultimately reward you with a beautiful new molecular structure. It can be hard work, but the exchange is a worthwhile one.
And such are my aspirations for this blog.