Yoda

I learned this the hard way. An academic career is not for me. Luckily I realized this relatively early, and worked hard to obtain transferable skills in programming and data analysis during my PhD, so that I was able to land a very nice position in the industry sector.

Speaking as someone with two MSc and one PhD in quantum chemistry, my advice is to seriously consider why you want to get a PhD. If you know that research is what you live for, and you know that you have it in you to succeed in academia, then a PhD is the first step towards an academic career. If, however, you have doubts as to whether you want to give up your free time or give up on having a family, or if you are not sure that doing research is what you want, then a PhD might not be correct.

@pentavalentcarbon I see. Thank you for good advice!

@pentavalentcarbon Thank you! And it is correct to refer to the CI expansion terms as "configurations" or "electron configurations"? I am working on a presentation about GASSCF/SplitGAS, and I don't want to say something stupid! :)

Question: Could the Hartree-Fock wave function be considered as a CI expansion where all terms are zero except for the ground state configuration? (I think the CI expansion uses configuration state functions and not slater determinants, but is the idea correct?)

bonding and anti-bonding, is what I meant concerning the active space

relevant study: pubs.acs.org/doi/ipdf/10.1021/ct4007844

nonbonding orbitals on the oxygens (p orbitals perpendicular to the ring). The study I am going to compare to did CASPT2 geometry optimisations, so I was going to do the same to check my calculations. Then I wondered whether the CASPT2 part needed to be part of the geometry optimisation, or if I only add the correlation to the CASSCF-optimized geometry - which, btw, is different from the published one. For the record, I use 12 active electrons in 10 orbitals.

@Martin-マーチン My system is 1,2-dioxetane. I am studying the thermal dissociation leading to chemiluminescence previous studies include. Right now I am trying to find and optimize the transition state. CASSCF is necessary due to the multiconfigurational nature of the dissociation, and I also need to correctly describe some excited states that become degenerate with the ground state along the reaction coordinate. The active space is the sigma bonding and bonding orbitals (CC', CO, C'O', OO) and the

when performing a CASPT2 geometry optimisation, should I do the CASPT2 part only on the converged CASSCF geometry, or include CASPT2 for each iteration? I am currently doing the latter, but it is taking ridiculously long. Btw, this is a transition state optimisation.

anyway, factor (b-a)/2 at the start of the approximation, should be in units of meters, right? So the integral units become m^7/mol, and not m^6/mol. How go around this?

wow, mathjax not working in here, apparently

$J (\lambda) \approx \frac{\lambda_{i+1} - \lambda_i}{2} \left[ F(\lambda_i) \epsilon_i \lambda_i^4 + F(\lambda_{i+1}) \epsilon(\lambda_{i+1}) \lambda_{i+1}^4 \right]$

hi. I am trying to numerically integrate and the spectral overlap integral using the trapezoidal rule. However, I think the units gets messed during the approximation. The integral is $\int F(\lambda) \epsilon (\lambda) \lambda^4 $. So, if the wavelength is in m, and the molar absorption coefficient is in m^2/mol, the integral should come out in m^6/mol. However, looking at the trapezoidal rule:

Consider a fluorescence resonance energy transfer (FRET) system. You need the donor emission spectrum to overlap with the acceptor absorption spectrum. But they don't. How fix that? I can't think of anything. It should be possible to lower the emission energy with a filter, but you can't put a filter in-between the donor and acceptor, which are separated by something like 50 Å. So, can you make a chemical change to the donor or acceptor that change the spectra in a desirable manner? Dunno.

Not yet, are you in a chem program?

Or, alternatively, blue-shift the absorption spectrum of a molecule?

Random question: Is there a way to red-shift the emission spectrum of a fluorophore?

Lol, I am sorry if my picture causes discomfort! Is it my face itself, or the fact that it is squashed? ;)

I should study for an exam. Why am I on Chemistry SE??