Questions tagged [water]

For modeling of H2O or H2O clusters.

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5 votes
1 answer
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Simulating autoionization of small molecules using DFT or AIMD

From what I’m reading, simulation of autoionization in liquid substances is hard to do using gas phase DFT or AIMD[1][2][3]. I am using ORCA to do my work and I must confess that I’m shocked to see ...
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3 votes
0 answers
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MD calculations for RO in the materials studio software

To study the SiO2, polyamide and two layer SiO2-polyamide as the membranes in the reverse osmosis desalination of saline water I used the Materials Studio software to model the systems. My question is ...
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11 votes
0 answers
132 views

Applicability of GFN-FF force field and other xTB methods for dynamics of ions in water

I am working on a project on water clusters with ions in them. One of the problems that I ran into quite early on was that good parameters are not available for highly charged ions such as $\ce{Al^3+}$...
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7 votes
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55 views

How to calculate small and wide-angle X-ray scattering spectra for the hydration shell restricted by a distance radius criteria

My main aim is to extract the SWAXS spectra for the hydration shell surrounding a solvated molecule and I am unfamiliar with the idea of excluded solvent volume. I tried looking online but many ...
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10 votes
0 answers
160 views

Setup for 4-point flexible water model [closed]

I tried to search online if there are examples or suggestions on how to set up a 4-point flexible water model, such as TIP4P/2005f, qTIP4P/f, TIP4P/$\epsilon$ FLEX, etc., but there's no clear example ...
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6 votes
1 answer
94 views

How to obtain electron charge density per unit volume about a water molecule using SlowQuant?

@Nike Dattani's answer to How to “get my feet wet” in Density Functional Theory by simulating a water molecule using Python recommends SlowQuant. I've used the install instructions for Linux on my ...
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8 votes
0 answers
99 views

How to reproduce 2D small-angle X-ray scattering (SAXS) interferogram of water via ab-initio MD methods?

I am trying to reproduce the 2D SAXS interference pattern of bulk water via ab initio MD methods as shown in the figure below: The main aim is to recreate figure (a) via averaging MD configurations ...
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6 votes
1 answer
104 views

Do we have specific benchmarks for the speed of a simulation of an empty water box with different water models?

I'm looking for a simulation of different water models (TIP3P, SPC/E, TIP4P, water models with flexible bounds) where the differences in simulation speeds on a common architecture are really seen. ...
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9 votes
1 answer
77 views

What is the state-of-the-art in current flexible water models?

Do we have water models so far which are flexible? How good can they model specific properties of water and are they currently used with force fields and in actual simulations?
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