Writing third-derivative tensor in normal coordinates

Find answers or ask questions regarding Dalton calculations.
Please upload an output file showing the problem, if applicable.
(It is not necessary to upload input files, they can be found in the output file.)

Post Reply
afca
Posts: 19
Joined: 11 Nov 2013, 01:23
First name(s): Antonio
Last name(s): Arapiraca
Affiliation: CEFET/MG
Country: Brazil

Writing third-derivative tensor in normal coordinates

Post by afca » 07 Mar 2016, 21:33

Hi,

In a vibrational averaged effective geometries calculation, the dalton code calculate the entire third-derivative tensor by numerical differentiation of the full molecular Hessian in Cartesian coordinates and after that transforming the Cartesian third-derivative tensor to normal coordinate, but the code only writes the Cartesian third-derivative tensor.

Can someone help me to write the third-derivative tensor in normal coordinates in order to know which constant correspond to what set of vibrational mode indices?

Best Regards
Antonio

PS: I can calculate the third-derivative by taking the second derivative of the molecular gradient using the .NORMAL flag, but I'm avoiding numerical instabilities

taylor
Posts: 545
Joined: 15 Oct 2013, 05:37
First name(s): Peter
Middle name(s): Robert
Last name(s): Taylor
Affiliation: Tianjin University
Country: China

Re: Writing third-derivative tensor in normal coordinates

Post by taylor » 08 Mar 2016, 10:21

I am not completely clear what you're asking for here. Do you want to change/extend the printout from the code to print the transformed 3rd derivatives, or do you want to look at a specific case? If the latter, it is probably easier to do it "by hand" (most likely, e.g., with a spreadsheet or with Mathematica/Maple/etc.) as a one-off.

Best regards
Pete

afca
Posts: 19
Joined: 11 Nov 2013, 01:23
First name(s): Antonio
Last name(s): Arapiraca
Affiliation: CEFET/MG
Country: Brazil

Re: Writing third-derivative tensor in normal coordinates

Post by afca » 08 Mar 2016, 22:35

Hi Pete,

Thanks for your reply. I want to extend the printout to print the transformed 3rd derivatives. Something like that some level of print.

kennethruud
Posts: 255
Joined: 27 Aug 2013, 16:42
First name(s): Kenneth
Last name(s): Ruud
Affiliation: UiT The Arctic University of Norway
Country: Norway

Re: Writing third-derivative tensor in normal coordinates

Post by kennethruud » 09 Mar 2016, 05:31

I think you can achieve such a print out by using a print level higher than 2 in *VIBANA.


Kenneth

afca
Posts: 19
Joined: 11 Nov 2013, 01:23
First name(s): Antonio
Last name(s): Arapiraca
Affiliation: CEFET/MG
Country: Brazil

Re: Writing third-derivative tensor in normal coordinates

Post by afca » 10 Mar 2016, 20:35

Hi Kenneth,

Its works very fine. Now I'm writing the cubic force field in terms of normal modes.

Thank very much

Antonio

Post Reply

Who is online

Users browsing this forum: No registered users and 7 guests