h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Hi, I thought I'd post that here, because it would be too OT in the PR thread.

So, you do surface science, eh? Wasn't too hard to guess. Most people do catalysis in p-chem, and most of it is surface science, so I had a good chance getting it right. I do single-molecule spectroscopy, you know... lasers, fluorescent organic dye molecules, homeopathic dilutions. That kind of stuff. My field is remotely connected to catalysis, since my job is to characterize the behaviour of individual molecules in molecular sieves. I see them moving around, turning round, emmitting different spectra, going to places they shouldn't go - but I haven't figured out how all those things add together.

Dietrich Menzel. This guy should be well known in your field. Ever heard of the MGR model (Menzel Gomer Redhead)? It's about ultra fast electron dynamics of adsorption and desorption. That guy looks at NEXAFS, XPS and Auger spectra and finds out what the electrons are doing when the bond between adsorbate and substrate is breaking - with a resolution of sub-femto seconds. (He looks at model systems, like CO, Ar, N2 on Cu(100) or Ru(110).)

I look at real systems. Crystals with cracks and defect sites, at room temp. The real stuff. Cannot do ab initio and fancy calculations. I just have to look and look and look. And then find out some correlations...

H

That's awesome - I'm somewhat familiar with single molecule spectroscopy, we had a whole bunch of seminars on it last year. Fantastic stuff, watching the movies of the molecules. Those were some of the best seminars we've had. I think it's because that's stuff that pchemists have been imagining in their heads for the last century - and now we finally get to see it for real. I think this must be how people felt when the first STM pictures were shown.
I've often felt that my (and my colleagues) style of studying catalysis is way too far removed from the real world. In my limited knowledge I know of one group that has used UHV studies to design and build and patent a real live honest to goodness catalyst. I think there needs to be more of that, otherwise what's really the benefit of all these UHV studies?


Anyway, I have heard of the MGR model, but I'm not familiar. That's my bad - thanks for the info, sounds like great stuff to read about. I'm going to look into it.

BTW, good ref to the homeopathic dilution - I guess you read that article also? I don't personally have any papers out yet, but if either of us do we should exchange - I'd love to read about your work. Anyway, talk to you soon.

dave

Wow! So the usual suspects of the single molecule community have been doing their homework and spreading the word... Glad you liked it. The good thing about single molecules is that you don't have to disentangle the whole ensemble, it's quite wysiwyg. (I think the enchantment fades somewhat after you've seen the same stuff many times. But then again, from time to time I get to see one or the other oddballs - people would find me staring at a screen full of noisy mumbo-jumbo like a teenager seeing his first porn. I guess I've become a .)

The MGR thing is nice, but then again it might not be that imprtant. It's just that during the intro the chairman made such a fuss about it that I thought Menzel is a real big-wig.

Homeopathy: yes, f'course. I mean, I'm a single molecule guy - I have also observed how single molecules (5 or so) can kill a cell. BUT, homeopathy (!!!) that's too much, and all that mumbo-jumbo about energies being stored in water. Imagine the noise? I am in a particularly desperate position, because here in Germany Homeopathy is widely accepted taught and all believe it (even people who should know better). It's a up-hill battle. (Have you read my comment in that convo? I had an experience where 'homeopathic' treatment worked.)

About exchangin' literature. Do you mean RL publications? Like Science and Nature and stuff? (just kidding... the stuff I do won't be up in science unless it cures cancer and tastes like strawberries - there's quite some bio-bias these days, isn't there? - My boss published in science last year because he (or rather the PhD folks) saw single viruses on their infection pathway into a living cell - using single-molecule spectroscopy. Big thing. The community went bananas - he was very proud of that. I think he is a good communicator.

HELL

Yeah, MGR probably is big, but my group doesn't do any XPS, and my advisor is extremely distrustful of any calculation, which is sometimes the only way they get anything out of XPS. So we're just not that familiar with it. But I'd like to be...

Yeah that homeopathy stuff is pretty silly. I have always run into and had friends who have been into that or gotten into it, but I never new anything about it so I never said anything or tried to argue. Now I'm still not going to say anything. I think some people need something mystical like that, why shatter it. I'm in the US, but I don't think I could deal if it was everywhere and was in my face. Anyway, I had a girlfriend once who was in med school, and her attitude was "hey, if it makes them feel better, that's the bottom line." I try to remember that when I start to get pissed off at the chanting.

BTW that was a good tie in to the communication article you had in the homeopath post! I think you could replace homeopathy with GM, or any topic of choice there.

Yeah, I was talking about RL publications. I currently don't have any, but I could tell you the cool ones that have come out of our group. I'd be particularly interested in that science paper where they watched the virus going to work, that sounds awesome. I can see why everyone went nuts.

So when you do single molecule spectroscopy, what's your setup? Are using near field micro fabricated tips, or how do you do it?

My advisor's big complaint about single molecule spec is that (by our standards) those molecules are "practically visible to the naked eye". Obviously a -slight- exaggeration, but since we work with H2, C2H4, CH4, and the biggest one ever was C6H6, you get an idea of our perspective. Have you ever heard of Wilson Ho? He used to be at Cornell, now he's at UC Irvine. He does vibrational, "single molecule" spectroscopy using STM tips of molecules like C2H2 on surfaces. Of course, as you pointed out earlier, these conditions aren't very realistic (4 K, takes 8 hours per scan).

Anyway, so how's Germany treating you? When I'm done I'd like to do a postdoc in Europe somewhere, I'm not sure where exactly yet. I've been on vacation to spain and france (very short) but I'd like to actually try living over there, I've never done study abroad. Any recommendations?

dave

Wilson Ho! Sure. He's been here some time ago, he probably knows our people too.

Homeopathy. Yes sure, "as long as it makes them feel better". But if a doctor wants to prescribe "homeopathic" stuff to my daughter when she in reality needs cortisone (she has skin-rash sometimes) I get mad. I later learned the doctor was relieved when he leart that I am a chemist (ok, p-chemist). He would usually prescribe cortisone, but these days he has to be afraid of losiong patients if he does that, so he offers homeopathic stuff first and then persuades them to go for cortisone. Here in Germany people think alternative medication comes first, only if you don't have another chance you may go for common medicine - I think it should be the other way round. I mean, Homeopathy worked for me, people need mumbo-jumbo, why not. But here in Germany it's reached an absurd level.

RL publications: The stuff I do is not nearly as sexy as the virus stuff of my boss' other group, but I think it's more thorough. I prefer good papers with bullet-proof maths instead of shiny model pictures. But that's just me, it's a bit unfair because you can sell that virus stuff a lot better... But that's life.

Here the refs - My stuff:
Journal of Physical Chemistry B 106 (2002) 5591.

Virus stuff:
Science 294 (2001) 1929.

My setup: I do confocal microscopy, because I want to look into the *inner* side of a microporous material, and not just the surface - you know all kinds of goo there on the surface. So basically it's a microscope, a bunch of lasers and sensitive detectors. "practically visible to the naked eye" Indeed, the eyes are sensitive enough to detect the fluorescence of an individual molecule. The problem is filtering the laser out (OUCH!). But he's right, we can only use bulky big-ones, that's the main drawback of SMS at the mo'. However, you can still learn a lot using the dye molecules as probes. For example for ultra-fast dynamics, or probing the interior polarity, or the homogeneous loading of dyes etc etc (I could go on forever justifying why I do the stuff I do...)

Germany: Nice place. Good food. Found my wife here. My kids were born here. It's OK. But I am not staying here forever. You know, it's the little things. But it's probably like that anywhere. So I guess it's not the Country, it's just me. The good news is that my wife shares this view...

Studying, post-doc etc...: Germany (still) has a good reputation. And a lot of money. Switzerland, France and Britain of course too. Scientifically speaking I dunno about the other countries, maybe the Netherlands. I think, for the other countries, you have to be very specific in your search for a good place to do your post-doc.

About living here, you know the old truth: Living in a place is different than spending vacation there. I can only speak for Germany as I don't know the other countries (I've been there, sure, as a tourist). Germany's a nice place to live. The infrastructure is excellent. People speak English. It's in the middle of Europe, so if you want to use it as a base to see the rest it's quite interesting to be right in the middle.

Well...

What about you? Your setup? Where are you exactly in the United States? Are you married? What are you going to do after finishing the PhD? Are you sure you want to do a post-doc? Questions...

HELL

Well, I never would have guessed that homeopathy had reached such extereme levels anywhere in Western Europe. That's kind of frightening. Around here, it's kind of a choice thing. You either go to one or the other. If you go to a regular doctor, chances are they won't ever mention homeopathy. Maybe that's good, maybe it's bad, but frankly I don't really like the idea of having homeopathy be my only initial first choice option. I'd like to be able to skip that and move on...

I think I've heard some stuff about the confocal microscopy setup before, and now that you mention it I'm starting to remember some of the dye molecules. I'll read your paper and then maybe I can ask some intelligent questions.
Thanks for the advice on Germany. I've never actually even visited Germany, but I figured basically on those countries you mentioned. The only additional one I had considered was Denmark, because I've seen a lot of UHV surface science papers come out of there.

So we're working using an ultra-high vacuum chamber to study a nickel single crystal. We've been depositing sub-monolayer coverages of Gold atoms onto the surface to study the properties of the resulting "surface alloy". Our main tool that we use is Electron Energy Loss Spectroscopy (EELS). It's basically a vibrational spectroscopy (like IR and Raman), except that it uses a "monochromatic" beam of electrons instead of light to detect the vibrational frequencies. The electrons hit the crystal with say 5 eV +/- 40 cm-1 of energy, and then are collected as a function of scattering angle & energy. Most electrons scatter elastically, but a very few cause a vibrational excitation, and lose a quanta of vibrational energy. So the difference in energy between the elastic and the inelasticly scattered electrons is the vibrational energy of the species on the surface.

Anyway, I'm in Boston right now. I want to a post-doc when I'm done, because 1) I have the rest of my life to work at a "regular" job 2) I may want to try for academia (if possible) 3) I want to live in Europe for a bit.
Mainly 1 & 3, I think reason 2 is a long shot. I'm not married, so that makes things a lot easier.

Well, I'm looking forward to reading those papers! Talk to you soon,

dave

Well, hi,

A week went by, and today we had another seminar (it's every wednesday). I tried the paying-attention method. but today the guy was a real messy communicator. I drew cartoons instead. I just thought I'd let you know.

See ya.

HELL

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Huh?

Yeah, what happened with 8 & 9? that's unexpected. Maybe I ticked someone off