Comments on: The importance of being complete.

By: Au and Pt π-complexes of cyclobutadiene. « Henry Rzepa

Au and Pt π-complexes of cyclobutadiene. « Henry Rzepa — Thu, 16 May 2013 08:42:47 +0000

[...] this time is eliminated by forming an allyl cation on the ring. I have described this mode in another post, commenting on the effect when a guanidinium cation interacts with [...]

By: Dynamic effects in nucleophilic substitution at trigonal carbon. « Henry Rzepa

Mon, 16 Jul 2012 05:18:19 +0000

[...] thoughts in fact followed a point I have been making here recently, the principle that modelling a complete system is probably better than a partial one. Now, if you look at Figure 1 of the Singleton [...]

By: Joining up the pieces. Peroxidation of ethyne. « Henry Rzepa

Joining up the pieces. Peroxidation of ethyne. « Henry Rzepa — Tue, 10 Jul 2012 05:51:50 +0000

[...] with modelling a cation without a counter-ion, I added one. I noted that the cyclobutadiene+ ion pair was more stable in this more complete [...]

By: Violations. There are none! Part 2. « Henry Rzepa

Violations. There are none! Part 2. « Henry Rzepa — Mon, 26 Dec 2011 10:39:48 +0000

[...] I had shaved off the four benzo groups (blue) in the time honoured computational tradition of clearing away distractions. Unfortunately, it became clear as the story unfolded that the benzo groups had a distractingly [...]

By: The colour of purple is … not orange but mauve? « Henry Rzepa

The colour of purple is … not orange but mauve? « Henry Rzepa — Thu, 27 Oct 2011 07:41:27 +0000

[...] the principle of completeness, it is important to include a counterion. And because the colour mauve is recorded in methanol [...]

By: Henry Rzepa

Henry Rzepa — Mon, 26 Sep 2011 11:49:10 +0000

I do not have a comprehensive recipe, and its clearly a need for someone to develop methodologies in this area.

What I did have to do to optimise the ion-pair in the (relatively flat) potential is to calculate 2nd derivatives at EACH step of the optimisation! Wow!

By: Bogdan Marekha

Bogdan Marekha — Mon, 26 Sep 2011 10:44:51 +0000

So what is your recipe to solve problems with unsymmetrical multiatomic ion pairs? One has to try as many initial configurations as he can make up and also include various orientations of ions relative to each other? What about the initial separation between ions in the starting configuration?

P.C. I’m talking about the situations where it is unaffordable to run a complete MD/MC simulation.