Messages

31

General Questions and Answers / Re: Relaxation problem

« on: June 24, 2014, 13:27 »

Dear Dr Zh,
Firstly, thank you very much for your  Fast Replay, for the geometry of the system , i firstly optimize the molecule by Gaussian 09 before i relaxed it between two electrodes in VNL, but the question i want to ask, If the position of the molecule between two electrodes can affect the time of relaxation   if the answer is Yes, How can i Justify this distances
Kind Regards,
Khattab    

32

General Questions and Answers / Relaxation problem

« on: June 23, 2014, 17:07 »

Dear All,
I want to relax a tow probe system, my system consist of two rings but the process is very slowly , can any one guide me how to relax this system simply , how can i set the parameters of relaxation like Force tolerance and Trust radius to make the process fast
Note:- i study trend between some molecules so i don't care about accuracy, only i want to relax these molecules before i study some parameters.
Any help please   
Kind Regards,
Khattab

33

General Questions and Answers / Re: I-V Curve of BDT Device

« on: May 30, 2014, 11:23 »

Dear Martinze,
Thank you very much for your replay and merry thanks for your interest to my topic .
Regards,
Khattab

34

General Questions and Answers / Re: I-V Curve of BDT Device

« on: May 28, 2014, 18:00 »

Dear Dr Umberto Martinze & Dr Anders Blom,
Firstly, Thank you for your rapid replay.
Secondly, I am so sorry for my delayed replay .
Thirdly, I follow your guides and the attached file is comparison between the published I-V curve (Computational Materials Science 27 (2003) 151-160) and the curve i calculated, is this is right??/
Kind Regards,
Khattab

35

General Questions and Answers / I-V Curve of BDT Device

« on: April 26, 2014, 17:19 »

Dear All,
I want  to calculate Some parameters for BDT , so recalculated the I-V curve and Transmission spectra for BDT and compared them with reference paper ( Computational Materials Science 27 (2003) 151-160), Transmission spectra curve i calculated is in a good agreement with the published curve in Fig(2) in the paper, but unfortunately  I-V curve i calculated is not Like published curve in Fig (4) in the paper.
The attached file is the curve i calculated.
Could anyone  Help me please 
Kind Regards,
Khattab

36

General Questions and Answers / Re: Number of cores

« on: April 11, 2014, 19:54 »

I will try it,thank you.
Regards,
Sayed

37

General Questions and Answers / Re: Number of cores

« on: March 31, 2014, 16:34 »

Dear Dr Anderson Blom,
Firstly thank you for your replay, but  want to till you that i run ATK on windows O.S not Linux so, how can i do this on windows?
Regards,
Khattab

38

General Questions and Answers / Number of cores

« on: March 29, 2014, 17:24 »

Dear All,
Kindly, i running ATK on workstation which has 8 core, i want to know the number of cores used for each process.
Kind Regards,
Khattab

39

General Questions and Answers / Re: Relaxation question

« on: March 26, 2014, 14:52 »

Dear Dr Zh,
the molecules i worked on it i firstly optimize them through G09, then i put the molecule between two electrodes as indicated in the ATK tutorials, in this case if i need to optimize tow probe system ( optimization is time consuming process )
Note i want to calculate parameters like, transmission spectrum, density of sates and current.
Kind regards,
Sayed

40

General Questions and Answers / Re: Relaxation question

« on: March 26, 2014, 14:34 »

Merry thanks for you.
Kind Regards,
Sayed

41

General Questions and Answers / Re: I-V curve of BDT divese

« on: March 19, 2014, 17:19 »

Dear Dr kstokbro
Firstly, thank you very much for you replay, i use the version 2008.10, i know this is old version but i want to help me to calculate I-V cuve through it, if you help me i will appreciate this a lot.
Kind Regards,
Sayed

42

General Questions and Answers / I-V curve of BDT divese

« on: March 19, 2014, 16:10 »

Dear All ATK Stuff
Firstly, i am sorry for my very simple question but i am still new beginner. 
I redid the calculation of transmission spectrum and I-V curve for DTB(Dithiol benzene) which calculated in the paper [ Computational Material science 27 (2003) 151-160] figure 2 and 4. when searched ATK forum i found the same question in the forum on this link http://quantumwise.com/forum/index.php?topic=1617.0
when i calculate transmission spectrum the curve i get went  i good agreement with the curve in the paper, when i tried to calculate I-V curve in the same range from 5.6 to -5.6 volt and interval is 0.1 like the paper, i set the parameters as K point (1,1,500) and number of points 113 point . i didn't get a curve but when i drop the vnl file in the result browser i get this message ( Current: 3.06014542552e-009 A)

My questions are:-
Q1:- Why i didn't get a curve??
Q2 :- IF this mean that i should calculate the current for each voltage separately, if this is true how can i do this, and how can i set the values of left electrode and right electrode  ?
note :- the attched file is the output file for I-v calculations
Kind Regards,
Sayed
 

43

General Questions and Answers / Relaxation question

« on: March 17, 2014, 10:34 »

Dear All,
How can i relax my two probe system before starting calculations on it.
Regards,
Sayed

44

General Questions and Answers / Re: Transmission spectrum error

« on: March 15, 2014, 20:06 »

This version of ATK is no longer supported, please try the latest version.

Dear Dr Kstokbor
Thank you very much for your replay , but whatever the version we use i have general question i hope to replay me on them.
Q1:- If i began the calculation of transmission spectrum from the check point of the optimization if this affect the values of transmission coefficients ?? or if the optimization affect on the transmission spectrum???

Q2:- How can i relax the two probe system in order to begin the calculations on it.
Regards,
Sayed

45

General Questions and Answers / Transmission spectrum error

« on: March 14, 2014, 05:11 »

Dear All
I want to calculate some parameters like transmission spectrum and density of state for a two probe system by ATK, i carried optimization on gaussian 09 then, i calculate the transmission spectrum and DOS by ATK and i get the normal termination, when i want to optimize the structure by ATK  in order to relax the structure and began the calculation from the check point file of the optimization i get different curve for DOS than the 1st curve of DOS, for transmission spectrum  the values of all transmission coefficients is zero  which also different than the 1st curve. My questions are:-
1- If the optimization affect on the values of DOS and Transmission spectrum ?
2- How can i relax the system on ATK??

Note:- i use  version  2008.10 of ATK
Regards,
Sayed