exercises:common:chg
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**Charge density difference analysis** takes the difference between charge densities of the system of interest and a reference one and plots charge redistribution due to chemical bonds. | **Charge density difference analysis** takes the difference between charge densities of the system of interest and a reference one and plots charge redistribution due to chemical bonds. | ||
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+ | $\Delta \rho = \rho_{AB} - \rho_{A} - \rho_{B}$ | ||
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+ | where $\rho_{AB}$ is the total charge (or electron) density of the whole system, $\rho_{A}, \rho_{B}$ are the density of the corresponding isolated system. | ||
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+ | It requires three single-point calculations of system AB, A, and B to print the [[https:// | ||
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+ | One can use [[https:// | ||
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+ | < | ||
+ | cubecruncher.x -i AB.cube | ||
+ | cubecruncher.x -i AB_A.cube -subtract B.cube -o chg_dif.cube | ||
+ | </ | ||
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+ | This type of analysis is also useful in the case of time-dependent calculations. In this case, the difference would be taken over time, with respect to some reference snapshot (e.g. ground state). | ||
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+ | $\Delta \rho (t-t_0) = \rho(t) - \rho(t_0)$, | ||
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+ | where $\rho(t)$ is the electron density at time $t$, and $\rho(t_0)$ is the reference electron density. | ||
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+ | < | ||
+ | cubecruncher.x -i elec_dens_t.cube -subtract elec_dens_t0.cube -o diff_t-t0.cube | ||
+ | </ |
exercises/common/chg.1666105011.txt.gz · Last modified: 2022/10/18 14:56 by jglan