CCL:G: chemcraft, cubegen and density

[veronica ferraresi <veroferraresi[*]gmail.com>]

 Hello,
It is not
 clear from your email if you need spin density or total density.

To
 generate the cubefile:
 cubegen  memory kind fchkfile cubefile npts
 format

 The parameters, which are not case-sensitive, have the following
 meanings:

memory
Amount of dynamic memory to allocate in words. A value of 0 implies a machine-specific default value.

 kind
 A keyword specifying the type of cube to generate

MO=n: Molecular orbital n. The keywords Homo, Lumo, All, OccA (all alpha occupied), OccB (all beta occupied), Valence (all valence orbitals) and Virtuals (all virtual orbitals) may also be used in place of a specific orbital number. There is no default for n, and an error will occur if it is omitted.

Density=type: Total density of the specified type.

Spin=type: Spin density (difference between α and β densities) of the specified type.

Alpha=type: Alpha spin density of the specified type.

Beta=type: Beta spin density of the specified type.

Potential=type: Electrostatic potential using the density of the specified type.

The type keyword is one of the single density selection options that are valid with the Density keyword: SCF, MP2, CI, QCI, and so on (note that Current is not supported). The fdensity, falpha and fbeta forms request the use of full instead of frozen-core densities. The default is SCF.

I copied all that from Gaussian help.

Verónica.

2009/4/12 Madi madi7sk]^[gmail.com <owner-chemistry*|*ccl.net>

Sent to CCL by: Madi [madi7sk]*[gmail.com]

Hi David,

It says "Electron density from Total SCF Density" on the left work area.
Is there a command line that i need to use during the making of cube file
to get "electron density from spin"?. I tried changing the contour value to
0.0008. the blob gets much bigger. when I go to higher contour values,
size of the blobs become smaller. The blob stays in single colour though.
There are other parameters such as values range and scale.  Are there
appropriate
settings for those that i need to use?

Thank you for your help
Madi

On Sun, Apr 12, 2009 at 2:22 PM, Close, David M. CLOSED##mail.etsu.edu

<owner-chemistry+/-ccl.net> wrote:
>
> Sent to CCL by: "Close, David M." [CLOSED(0)mail.etsu.edu]
> Madi:
>  When you open the .cube file, does a work area appear on the left that says "Electron Density from Spin" ?  If so, move down to the choice "Show Isosurface, and then click on the "Both Signed" option to the right.  You still may not see what you want because the Contour Value is too big.  Click on the Contour Value to make it below say 0.0008, and you should see positive and negative spin densities.
>  Regards, Dave Close.
>
> -----Original Message-----
>> From: owner-chemistry+closed==etsu.edu**ccl.net [mailto:owner-chemistry+closed==etsu.edu**ccl.net] On Behalf Of Madi madi7sk _ gmail.com
> Sent: Saturday, April 11, 2009 11:38 AM
> To: Close, David M.
> Subject: CCL: chemcraft, cubegen and density
>
>
> Sent to CCL by: Madi [madi7sk-.-gmail.com]
> Hi All
> I am sorry about not wording the question properly.
> I meant to ask how to see regions of high and low electron densities.
> Right now i am able to see only one colored blob on the molecule.
>
> Thanks
> madi
> On Sat, Apr 11, 2009 at 9:53 AM, Madhavan Narayanan
> madi7sk_._gmail.com <owner-chemistry[#]ccl.net> wrote:
>>
>> Sent to CCL by: "Madhavan  Narayanan" [madi7sk * gmail.com]
>> Hi,
>>
>> I converted my check point file to .fchk and then to .cube.
>> Then I tried opening it in chemcraft. When I opened it to view the electron density, I see only atoms with positive density. How do I get it to show me both positive and negative regions? I am very new to this and would appreciate any help.
>>
>> Thank you
>> Madi
>>
>>
>>
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