conductance of molecular devices

[sweta]

Hello all

Can you please tell me how we can find the value of conductance 'G' and HOMO, LUMO by calculating transmission spectra of molecular devices

Huang

[Anders Blom]

I strongly suggest you follow the tutorials, like
http://quantumwise.com/documents/tutorials/latest/ATKTutorialDevice
and
http://quantumwise.com/documents/tutorials/latest/MolecularDevice

It's all explained there. Also see the reference manual for a more general discussion on how the current and conductance are related to the transmission spectrum.

[sweta]

Thanx alot Sir.

As in your tutorial for molecular devices (Chapter 3), our calculation does not showing carbon, gold, hydrogen, sulphur in projection selector while calculating MPSH states. why it is so?

So how i should proceed further for calculating eigen states because our log file does not showing energy values like your manual log file.

[Anders Blom]

There is a small trick to that. If you start the Script Generator by dropping the original device configuration on it, and then remove it (select the DeviceGeometry block and press Delete on the keyboard), the projection selectors should be initialized correctly. After this you can insert "Analysis from File" and the Analysis blocks.

The problem is that without this, the widget doesn't know which configuration you have in the file, so it doesn't know what you can project on. The tutorial can be improved on this point, but I hope you manage now.

[sweta]

Thank you sir. It solved the problem.

Also in the same tutorial (chapter 4) when i run the script, a self-consistent calculation to calculate I-V curve characteristics, the script is failed. why?
what is the solution for that?
What changes i should make in the script?

The failed log file is attached with this mail.

[Anders Blom]

The log file you sent contains no error messages...

[sweta]

Sir you wrote in the manual (chapter 4 of ATK manual of molecular devices) that it will take overnight to run it (if not use parallel system) but our script finishes within 5 minutes and job manager showing script is failed.

so when i drop NC file by selecting analyzer to calculate I-V curve, it only shows a point.

Probably the reason for that the given script is unable to calculate current @ different voltages (if the loop is not working well)
so what changes i should take in the script??
Please help!

[Anders Blom]

Hm, your log file shows that it goes into the loop, sets the 0.2 V bias, and then just stops... Mysterious.
You didn't possibly, by any chance, run some other calculations at the same time, in the Job Manager? In this case, sometimes the log files can get mixed up, so that although it actually runs, the output goes into the other log window. Just a thought.

[sweta]

Sir i am running only one script at a time

[Anders Blom]

I don't have the NC file handy (au_dtb_au.nc), which is used as input in this script; do you think you could send it to me using http://letscrate.com? My email is visible in my profile.

[sweta]

Is this possible to attached NC file with this mail if not then i'll try to send it by http://letscrate.com

One more thing i want to know second time when i run the same script it shows


"This application has requested the Runtime to terminate it in an unusual way.
Please contact the application's support team for more information"

What does it mean and what is its solution

I attached the second failure script with this mail

[Anders Blom]

This is an indication that you don't have enough memory on the computer to run this script.

[sweta]

Kindly tell me how much memory is required for simulating the I-V characteristic script (page 20, ATK manual for molecular devices)

Thanks in advance!

[Anders Blom]

If your computer has 4 GB you should be ok. Less than that, on Windows in particular, you might run out.

[sweta]

I have core 2 duo processor 2.60 GHz and 6 GB RAM. Is it sufficient??