[Pw_forum] Help to learn

Faridul Isalm faridul at email.com
Sun Jan 6 10:10:23 CET 2008

Dear Sir,
I am a novice user of Quantum Espersso (PWscf).I use it on the CYGWIN platform. I did the examples successfully those are given with Quantum Espresso package. I am now trying to learn "band structure calculation" step. But I face the following problems:

1) when I run plotband.x, there need to specify "Efermi", but where I get this value. I look all output files, nowhere that is. such as for Si Efermi = 6.337, from where this value comes.

2)when this method is used for other materials such as SiO2, MnO2, GaAs, etc., then how can i specify their ibrav in the &system namelist. and also how can I know their celldm. 

3)when it is used for semiconductor materials, then which variables may need to specify in the &system namelist.

4)how can I determine the proper "ecutwfc" of a particular material. is it =kT?

5)I face a great problem when I use k-points {automatic}, then output of the band does not match with the given examples. But when I use 36 k-points that are given in the examples then it is ok. Now how can I choose the proper k-points for a particular material.

6)When I run xcrysden --pwo si.scf.out, then i get " the hardware does not support the stereo" error massage. My computer is "Intel Core2 Duo, 1.86GHz, 512MB RAM". how can i solve this problem.

I will be very greatful to you, if you kindly give me the solutions of the above mentioned problems. I want to learn about this method clearly. I will be very happy if you give me yours further valuable   successions that can help me to learn.

I am looking forward to hearing from you.
Thank you for your valuable time.

Dr. A.K.Md Farid ul Islam
Assistant Professor,
Dept. of Physics,
Carmichael University College, Rangpur-5004, Bangladesh

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