Jan Jensen
984 followers
984 followers
Jan's posts
Post has attachment
Finding the function that is its own derivative
I saw this "derivation" some years ago but now I can't find it.  If anyone knows the source please let me know. Let's say we want to find a function $f(x)$ for which $$\frac{d}{dx} f(x) = f^\prime (x) = f(x)$$ Well, how about $f(x) = x$?  f(x) = x \impl...﻿
Post has attachment
Where does the ln come from in S = k ln(W) ? - Take 2
Some years ago I wrote this post . Now I want to come at it from a different angle. A closed system spontaneously goes towards the state with maximum multiplicity, $W$. For a system with $N$ molecules with energies $\varepsilon_1, \varepsilon_2, \ldots$ we...﻿
Post has attachment
Computational Chemistry Highlight: March issue
The March issue of  Computational Chemistry Highlights  is out. CCH is an  overlay journal  that identifies the most important papers in computational and theoretical chemistry published in the last 1-2 years. CCH is not affiliated with any publisher: it is...﻿
Post has attachment
The Elephant in the Room of Density Functional Theory Calculations
Stig Rune Jensen, Santanu Saha, José A. Flores-Livas, William Huhn, Volker Blum, Stefan Goedecker, and Luca Frediani (2017) Contributed by  Jan Jensen While basis set convergence sounds straightforward (though time-consuming) it is hard to rule out that un...﻿
Post has attachment
Computational Chemistry Highlight: February issue
The February issue of  Computational Chemistry Highlights  is out. CCH is an  overlay journal  that identifies the most important papers in computational and theoretical chemistry published in the last 1-2 years. CCH is not affiliated with any publisher: it...﻿
Post has attachment
Biotechnology and drug-design: My latest paper explained without the jargon
Our latest paper has just appeared in the open access journal Chemical Science . It's ultimately related to biotechnology so first some background. Background Most biotechnology and medicine involves proteins in some way. Many diseases involve mutations tha...﻿
Post has attachment
Towards full Quantum Mechanics based Protein-Ligand Binding Affinities
Stephan Ehrlich, Andreas H. Göller, and Stefan Grimme (2017 ) Contributed by  Jan Jensen Erlich et al. presents absolute binding free energies for activated serine protease factor X (FXa) and tyrosine-protein kinase 2 predicted using DFT. Here I'll focus o...﻿
Post has attachment
RMSD and MUE versus Correlation Coefficient: a simple illustration of the difference
Here is a simple illustration of what the root-mean-square deviation (RMSD), mean-unsigned error (MUE) and correlation coefficient ($r$) can tell you about your data.   Imagine that the $x$-axis is experimental data and the $y$-axis is computed data in some...﻿
Post has attachment
What are the most important reactions in drug synthesis and stability?
This is a rough draft that I hope to flesh out based on feedback, i.e. "I'm not telling, I'm asking". Please leave a comment or tweet me I realize Synthesis 1. Aromatic electrophilic substitution of heteroaromatics 2. Suzuki coupling of heteroaryl halides 3...﻿
Post has attachment
Preprints and the speed of publishing
When I talk about preprints with colleagues some of them say "Oh, what's the rush?" or "Publishing is so fast these days. Why, my last paper was online 6 weeks after submission don't you know" and then go on to clean their pipe with a thoughtful smile or ge...﻿