I don’t have a huge amount of time to talk about it at the moment, but something kind of cool has happened. This is a small extension off my quantum chemistry series. For much of the last year, I’ve been putting huge amounts of time into ab initio calculation using the General Atomic and Molecular […]

# Tag Archives: Quantum Mechanics

## Quantum Physicist Self Evaluation

(This post was generated in response to a Quantum University Crank over the last month and tacked at the end of my Quantum University post. I left it there for the Quantum U jackasses to come and gawk and pretend their pseudoscience will give them some supernatural powers, but I also post it here because […]

## Grade A crankery at Quantum University (part 2)

This is a repost of a section of my original quantum university post. I decided that I wanted to put it up as its own blog entry so that it would have some opportunity to be read in its own right. A comment has lead me to believe that the august body of Quantum University […]

## The Organic Chemistry Lie

Fallout from my learning about Molecular Orbital theory and Hartree-Fock. I’ve said repeatedly that Organic Chemistry is along the spectrum of pursuits that uses Quantum Mechanics. Organic Chemists learn a brutal regimen of details for constructing ball-and-stick models of complicated molecules. I’ve also recently discovered that chemistry –to this day– is teaching a fundamental lie […]

## Building a Molecule; Time Spent in the Gap

How is a molecule built? Rather, what exactly is required to predict the electronic structure of a molecule using modern tools? I will use this post to talk about my time spent learning how to apply the classic quantum mechanical calculation of Hartree-Fock (note, this is plain old Hartree-Fock rather than multi-configuration Hartree-Fock or something […]

## The Quantum Mechanics in the Gap

A big cat’s paw of mine is trying to fill the space between my backgrounds to understand how one thing leads to another. When a biochemist learns quantum mechanics (QM), it happens from a background where little mathematical sophistication is required; maybe particle-in-a-box appears in the middle of a low grade Physical Chemistry class and […]

## Disagreeing with “Our Mathematical Universe”

My wife and I have been listening to Max Tegmark’s book “Our Mathematical Universe: My Quest for the Ultimate Nature of Reality” as an audiobook during our trips to and from work lately. When he hit his chapter explaining Quantum Mechanics and his “Level 3 multiverse” I found that I profoundly disagree with this guy. […]

## Interaction Picture

It’s not always about the cat. Here, I will show how to hop from the time dependent Schrodinger equation to the Interaction picture form. This post is intended to help recover a tiny fraction of the since-destroyed post I originally entitled “NMR and Spin Flipping part II.” I have every intention to reconstruct that post […]

## Chemical Orbitals from Eigenstates

(Edit 5-12-20: There’s a post-script here regarding a regret about my chosen title) A small puzzle I recently set for myself was finding out how the hydrogenic orbital eigenstates give rise to the S- P- D- and F- orbitals in chemistry (and where s, p, d and f came from). The reason this puzzle is […]

## Parity symmetry in Quantum Mechanics

I haven’t written about my problem play for a while. Since last I wrote about rotational problems, I’ve gone through the entire Sakurai chapter 4, which is an introduction to symmetry. At the moment, I’m reading Chapter 5 while still thinking about some of the last few problems in Chapter 4. I admit that I […]