Category Archives: Publications
Simulation of Raman Spectroscopy and crystal cell effects – Selenium Carboxylate Eur. J. Inorg. Chem.
Computing spectroscopic features of molecules is always an interesting challenge, specially when intermolecular contacts are into play. Take vibrational spectroscopy for instance, all the non-covalent interactions present in a solid will have an important effect on the the calculated frequencies and their intensities. However calculating the spectroscopical properties of a solid quickly becomes a daunting task.
My colleague and friend Dr. Vojtech Jancik asked me to calculate the Raman frequencies for a new compound: Selenoyl bis-carboxylate, which according to him was very hard to obtain due to the very nature of selenium. So we performed various calculations on the isolated molecule to reproduce the measured Raman spectrum but we soon realized that a calculation on the crystal cell was needed if we wanted to get a more thorough picture of the experiment.
The level of theory used was PBEPBE/LANL2DZ. Optimization of the title structure pointed to a low coordination capacity by carboxylate groups as evidenced by the longer Se -O-C=O distances and reduced Wiberg bond indexes. A blue shift was observed for all bands and so we calculated the Raman frequencies at the crystal structure which gave us a better correspondence between spectra. Finally we computed the Raman spectra for the full unit cell comprised of four molecules with which an excellent agreement was obtained (a scaling factor of 0.8 was used).
Unfortunately we failed to further extend this calculation to a larger system with four unit cells and 32 molecules apparently due to insufficient memory; the calculation just stalled and stopped without error after consuming its time in the queue. I’ll try to take a look into it some day.
You can read the whole story in: Synthesis and Crystal Structure of the First Selenonyl Bis(carboxylate) SeO2(O2CCH3)2
Lukas Richtera · Vojtech Jancik · Joaquín Barroso‐Flores · Petr Nykel · Jiri Touzin · Jan Taraba
Thanks for reading!
It was your idea. You had it. Or did it have you? But suddenly, you see it wrapped around someone else’s words. You read and gasp in denying shock. This can’t be! You read again trying to find your mistake, it is clearly a mistake on your part; to find it, you search for differences, preferably major ones that reveal that the identity of this idea is different to yours. You hope to just be mistaking it for yours. The wording is different, of course, you would have emphasized it differently, the way it deserved to be emphasized. But nevertheless its a mistreated version of yours. No matter what, this was yours. Was. Heartbroken, you try to save some face, by treating it differently; by treating it better!; by tending to those bits this third party is neglecting; by dumping it and getting a new and better one. You were so close. All in vain, for the fact is that this idea is no longer just yours, it seduced someone else’s mind and got brought to life by swifter hands. Now forever they will remain bound together as two celestial bodies are bound by gravity in the marriage of scientific annals, under the complicit auspice of editors and reviewers. Yes. You were the last to know this went on. It once made you feel so special, proud of your sparkling originality and your long hard work, brilliant even, but now you feel idle and exposed while in the dark.
You wish that at least you were perceived as a fool, as a laughing stock or even as an intellectual cuckold! But you are left worse than that: You are left with nothing. Empty handed. A runner up at best or part of the despised ‘me-too‘ kind, but only if you manage to get something out there at which the public scrutiny can roll their eyes. Still, that would be indeed better than having nothing to show for after all those long hours of shared intimacy with this idea. Angrily, you decide to blame others: technicians for delaying experiments; your collaborators for delaying revisions; your students for delaying data, and even the head of the department, maybe just for being other than yourself. You read again. The idea, no longer yours alone, stares back at you; no amount of hatred can change that. And then you wonder if you could have possible been on the other side before? You hope you have, for that means you are ahead in the game, but like in any game, sometimes you loose. Could your mind have been the seducing one before? You hope it has, for if it hasn’t it means you are playing alone in a corner of no interest to anyone, and what fun is that? What fun is a game in which you cannot win?
You mend fences. You accept that for this time someone was lucky but soon luck will come back and you will seduce other ideas; your hands will bring them to life and you will successfully collect the recognition for it, no matter how little the victory. Affairs with new ideas will come. Luck will come back. And it will come back to find you busily working or will not come back at all.