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**maziar****Member**- Registered: 2018-08-22
- Posts: 4

Hello,

Multiwfn returns zero for "negative surface area" when performing quantitative analysis of molecular surface (12) on the wfn of 3,4,5-trifluorotoluene and 4-nitrotoluene. The structures were optimized at b3lyp level with 6-31g(d,p) basis set.

Could anyone help me figure out what could be the problem and a possible solution to this?

Thanks very much in advance.

Here is the summary of calculation for 3,4,5-trifluorotoluene and I am using Version 3.5, release date: 2018-Apr-6 but I get the same problem trying Version 3.6(dev), release date: 2018-Aug-2.

================= Summary of surface analysis =================

Volume: 964.48414 Bohr^3 ( 142.92184 Angstrom^3)

Estimated density according to mass and volume: 1.6976 g/cm^3

Minimal value: 549.66960 kcal/mol Maximal value: 1105.01382 kcal/mol

Overall surface area: 546.75577 Bohr^2 ( 153.10723 Angstrom^2)

Positive surface area: 546.75577 Bohr^2 ( 153.10723 Angstrom^2)

Negative surface area: 0.00000 Bohr^2 ( 0.00000 Angstrom^2)

Overall average value: 1.31433044 a.u. ( 824.75549 kcal/mol)

Positive average value: 1.31433044 a.u. ( 824.75549 kcal/mol)

Negative average value: NaN a.u. ( NaN kcal/mol)

Overall variance (sigma^2_tot): 0.05805716 a.u.^2 ( 22861.09768 (kcal/mol)^2)

Positive variance: 0.05805716 a.u.^2 ( 22861.09768 (kcal/mol)^2)

Negative variance: 0.00000000 a.u.^2 ( 0.00000 (kcal/mol)^2)

Balance of charges (miu): 0.00000000

Product of sigma^2_tot and miu: 0.00000000 a.u.^2 ( 0.00000 (kcal/mol)^2)

Internal charge separation (Pi): 0.20965058 a.u. ( 131.55784 kcal/mol)

Surface analysis finished!

*Last edited by maziar (2018-08-23 17:14:51)*

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Dear maziar,

I have carried out the analysis for 3,4,5-trifluorotoluene, but did not find the same problem (I am using the least version 3.6(dev))

Below is entire output of Multiwfn of the ESP analysis on molecular surface

1.txt

Below is the .fch file I used, which was obtained by using "# B3LYP/6-31G* opt" keywords.

1.rar

Please carefully compare your data and my data to try to figure out the reason. If the problem cannot be solved, please upload your Multiwfn input file as well as Gaussian input file.

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**maziar****Member**- Registered: 2018-08-22
- Posts: 4

Dear Tian,

Thanks very much for taking time to examine the issue. It seems that this problem only occurs when I use wfn as input file. I switched to formatted checkpoint (fchk) as input file and the problem is resolved.

Thanks again for Multiwfn and your help.

Best wishes,

Maziar

*Last edited by maziar (2018-08-24 20:41:08)*

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I also tested corresponding .wfn file exported by out=wfn keyword

1.wfn

The analysis result is identical to .fch file. Probably your .wfn file is problematic.

BTW: Using .fch is always preferred. In the latest 3.6(dev) version, if you have Gaussian installed on your machine and .fch is used as input file, and meantime "cubegenpath" in settings.ini has been set to actual path of cubegen, then Multiwfn can automatically invoke cubegen utility in Gaussian package to significantly accelerate ESP analysis, see Section 5.7 of the latest version of manual.

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