Messages

1

General Questions and Answers / how to insert molecule

« on: November 26, 2010, 10:26 »

 Earlier I used 2008.10. I have recently started working on  new version 10.8.I am getting problem to set two probe system.From mini tutorial,I learnt how to make two probe.But I do not know how to insert molecule  and set device.Can any one help me.
Thanking you

2

General Questions and Answers / Re: molecular spectrum of neutral/oxidized molecule

« on: April 21, 2010, 23:50 »

Thanks for reply.What i want to know is exactly mentioned in the tutorial.Though i use 2008.10.Now i have to learn new one.
Thanks once again.I like this forum very much.It  helps me a lot.Thanks again for such wonderful forum.
with best regards

3

General Questions and Answers / Re: molecular spectrum of neutral/oxidized molecule

« on: April 20, 2010, 18:40 »

I  did not mean the oxidation what  you mentioned.What you said is the addition of oxygen.I mean,the removal of electron  from the molecule.I like to give examples,Fe2+ -(1e-) = Fe3+ , C6H6 - (1e-)=C6H6+,these are loss of one electron,oxidation.In the second example ,using ATK, molecular spectrum of C6H6 can be obtained.I want to know the procedure to obtain molecular spectrum   when 1e remove from C6H6.I hope now i am clear.
with best regards

4

General Questions and Answers / molecular spectrum of neutral/oxidized molecule

« on: April 18, 2010, 12:16 »

Dear All
Is it possible to find out energy level diagram after oxidation of molecule.In other words,how to find our energy spectrum of neutral and oxidized molecule.Please help.
with best regards
shank

5

General Questions and Answers / Re: HOMO/LUMO

« on: April 16, 2010, 10:00 »

Thanks.
I want to study I-V characteristics in the device structure Si/molecule/Hg. The experimental data is very interesting, where  we observed sharp decrease in current near 1V and again current  increases with voltage.  We also did cyclic voltammetry of the deposited film,it resemblances with oxidation of molecule.Now i feel, under the bias, if molecule get oxidized, then its HOMO/LUMO will change and that will effect current flow. If it is so, how we will study the I-V using vnl.
with best regards

6

General Questions and Answers / Re: HOMO/LUMO

« on: April 15, 2010, 08:36 »

Dear Blom
Thanks for reply and link.I want to draw enegy level diagram considering HOMO and LUMO with Fermi level of metal contacts in used.

with best regards.
shank

7

General Questions and Answers / Re: HOMO/LUMO

« on: April 14, 2010, 05:43 »

Just for clarification. If 0  level is Fermi level then LUMO will be always positive in molecular energy spectrum.But I found,LUMO is negative and is between HOMO and LUMO.

8

General Questions and Answers / Re: HOMO/LUMO

« on: April 14, 2010, 04:55 »

Dear Nordland
Thank you.
with best regards
shank

9

General Questions and Answers / HOMO/LUMO

« on: April 13, 2010, 20:15 »

Dear sir
I have calculated HOMO and LUMO of a molecule using vnl package.Now i want to know, with what respect  the energy values are defined.In other words, what does correspond to 0eV in molecular energy spectrum.Does this represent vacuum level? I am learning the theoretical aspect of the molecular energy level.Please help.
Thanking you.
with best regards

10

General Questions and Answers / Re: how to make cyclic molecule in molecular builder

« on: September 9, 2009, 16:47 »

thanks.

11

General Questions and Answers / Re: how to make cyclic molecule in molecular builder

« on: September 9, 2009, 13:16 »

Thanks for reply and ideas.I like to  know if geometry is optimized at -2V by applying constraints to electrode.Then change of conformation may be known.
with best regards.

12

General Questions and Answers / Re: how to make cyclic molecule in molecular builder

« on: September 9, 2009, 10:44 »

thank you very much. The  experimental data what I have  is when I scan bias from 0 to -2 around -1.3V   high conduction observed and when bias is reversed from -2 to 0V  current is low.So two  conduction states  are around -1.3v.So i have doubt when i will calculate tranmission spectra at -1.3V it will be only states for -1.3V irrespective of bias direction.If I proceed in one direction 0V as initial SCF and i calculate transmission spectra at -1.3V and again -2V SCF for initial value and calculate transmission at -1.3V.Will it work.i want to explain the reason for this type of I-V.this I-V was repaeted many times.waiting for suggestion.

with bets reagrds

 

13

General Questions and Answers / about IV

« on: September 8, 2009, 18:24 »

I have experimental I-V. I found while cycling the bias  , there is high conduction state in forward direction of cycle and low condution state at reverse direction.If I want to find out transmission spectra of such syatem.How should i go.One more query is it possible to get .nc file for each voltage while using iv curve module.So that once I-v generated i may restore .nc file at particular volatge and measure transmission spectra.

with reagrds

14

General Questions and Answers / Re: how to make cyclic molecule in molecular builder

« on: September 8, 2009, 11:27 »

thanks.

15

General Questions and Answers / Re: how to make cyclic molecule in molecular builder

« on: September 8, 2009, 06:58 »

Thanks alot.One more query is it possible to get I-V using iv curve module for voltage range -2 to2V.

with regards