# Tag Info

Accepted

### What are the parameters that need to be calculated to design the structure of a molecule?

Ah, yes, the fun of force-field building. For the answer to a simple geometry optimization, see I. Camps response below. Skip to the end if you want what is a more general answer to building an entire ...
• 4,066

### What are the parameters that need to be calculated to design the structure of a molecule?

All Gaussian jobs when completed without any error, will have, at the end of the output file, a phrase/thought/quote from someone famous. It is kind off an easteregg. My latest Gaussian successful job ...
• 19.2k
Accepted

### How can I decide on the order of different monomers in a co-polymer?

This is a question that cannot have a "right" answer. As mentioned in the comments, the answer would depend on the experimental system and on the specific properties you want to reproduce. ...
• 476
Accepted

• 613
Accepted

### How should I calculate total potential in a polymer chain?

You'll want to add up all interactions that you can, up to some appropriately chosen cutoff distance. Choose the VDW cutoff such that the total energy doesn't change much if you further increase this ...
• 613

### Simulating polymers using cellular automata?

Eventually, the question should be more detailed. However, for starters and in general, I would start by giving a cursory read to any wide piece of work that contains this problem, in order to get ...
• 1,421

### Why VASP calculates the elastic constant for another trigonal space group?

Elastic constants can be calculated using two approach, one with Energy-strain relationship and another with stress-strain relationship. The key ingredient in above two methods is energy or stress at ...
• 3,247
Accepted

### Discrete lattice polymer simulations

Ironically, there exist no on-lattice software for such a Flory-Huggins software. This is primarily because there are no set standards for running such simulations! Most people run their own DIY code ...
• 3,937
1 vote

### End-to-end correlation of polymers not decorrelating

The problem with this moveset is that it is too local. The best way to decorrelate polymer configurations is to run simulations with more aggressive moves, such as chain regrowth.
• 3,937
1 vote

### How to check for phase separation in polymer simulations?

Turns out the best way to spot phase transitions in polymers is to run the extended cell simulations and calculate surface tension, as seen in this paper: http://dx.doi.org/10.1063/1.3227905.
• 3,937
1 vote

### Generating topology for charged molecules

There are two options here and the choice depends on what you intend to do with your results. If you are going to perform QM calculations after MD, then you can just alter the charges as you outlined ...
• 1,496

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