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Chemistry Forums for Students => Physical Chemistry Forum => Topic started by: bnggum on April 02, 2021, 06:54:44 AM

Title: Electron density calculation - ORCA
Post by: bnggum on April 02, 2021, 06:54:44 AM
Hello!

Does anyone know how to print electron densities on ORCA? I am trying to construct a QSPR model to rationalize the reactivity of some organic compounds through electron density calculations. There is one code from the ORCA manual that prints electron densities near the nucleus but I believe those values are not useful for describing chemical reactivity. Is there another code/method that would work for this purpose? Thank you!
Title: Re: Electron density calculation - ORCA
Post by: Orcio_Dojek on April 05, 2021, 07:54:45 AM
ORCA prints Mulliken gross atomic charge - a partial charge which atom have. This is some quantitative information (for example +0,36 on C and -0,46 on O at -C=O in CH3-CH2-CHO).

However this doesn't give any information about localisation of charge at space.

Even if program would print that sort of information - 0,001 e- at x y z, and 0,002 e- at x y z+0,001 - imagine how hard it would be to read it.

I mean - it is possible - for example - N in pirydine lies in center (x, y, z = 0) and orbital σ (the one which is non-bonding) lies straight in z direction, but - it will be harder for other compounds.

I found that command "KeepDens" prints some information about electron density in separate (.scfp) file, but this is bunch of random letters.

How to really print it, I don't know since I used this program only few times.