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| 1:24:17 PM PDT - Thu, Mar 22nd 2012 |
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Dear all,
I've started learning about plane-wave DFT last month. My goal is to perform density of state calculations so I tried out the following NWChem example : http://www.nwchem-sw.org/index.php/Plane-wave_Density_Functional_Theory#Using_BAND_to_Calculate_the_Density_of_States_of_Diamond. The diamond-dos.dos was created in the perm directory. I've figured out that the first column of this file gives the energy in Hartree units and the second column is the density of states(DOS) and thus was able to generate the DOS plot that looks identical to the one on the web page. However, I have been trying unsuccessfully to find the units of the DOS. Firstly, is the latter defined as the number of one-electron states divided by the energy range (E,E+delta_E)/delta_E (cf. "SOLID STATE PHYSICS" by Ashcroft and Mermin)? If so what are the units of the one-electron energies?
Secondly, can anyone tell me what the field "np_dimensions" is? According to "Hard scaling challenges for ab initio molecular dynamics in NWChem:Using 100,000 cpus per second", np stands for the number of processors and npi/npj stands for the size of column(row) processor group. In NWChem, the directive is given as NP_DIMENSIONS <integer npi npj default -1 -1>. Do they correspond to the ones in the article? Lastly, the Nickel example gives the following input: np_dimensions -1 -1 4. What does 4 represent?
Thank you very much for your help.
Regards,
Bryne
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Bert Forum:Admin, Forum:Mod, NWChemDeveloper, bureaucrat, sysop
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| 3:16:09 PM PDT - Fri, Mar 30th 2012 |
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Yes, these dimensions correspond to the discussion in the article.
Bert
Quote:Brynetan Mar 22nd 8:24 pmDear all,
I've started learning about plane-wave DFT last month. My goal is to perform density of state calculations so I tried out the following NWChem example : http://www.nwchem-sw.org/index.php/Plane-wave_Density_Functional_Theory#Using_BAND_to_Calculate_the_Density_of_States_of_Diamond. The diamond-dos.dos was created in the perm directory. I've figured out that the first column of this file gives the energy in Hartree units and the second column is the density of states(DOS) and thus was able to generate the DOS plot that looks identical to the one on the web page. However, I have been trying unsuccessfully to find the units of the DOS. Firstly, is the latter defined as the number of one-electron states divided by the energy range (E,E+delta_E)/delta_E (cf. "SOLID STATE PHYSICS" by Ashcroft and Mermin)? If so what are the units of the one-electron energies?
Secondly, can anyone tell me what the field "np_dimensions" is? According to "Hard scaling challenges for ab initio molecular dynamics in NWChem:Using 100,000 cpus per second", np stands for the number of processors and npi/npj stands for the size of column(row) processor group. In NWChem, the directive is given as NP_DIMENSIONS <integer npi npj default -1 -1>. Do they correspond to the ones in the article? Lastly, the Nickel example gives the following input: np_dimensions -1 -1 4. What does 4 represent?
Thank you very much for your help.
Regards,
Bryne |
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Bert Forum:Admin, Forum:Mod, NWChemDeveloper, bureaucrat, sysop
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Forum Vet
Threads 5
Posts 598
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| 3:20:49 PM PDT - Fri, Mar 30th 2012 |
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And, the third dimension refers to the distribution over k-space vectors (parallelization similar to VASP).
Bert
Quote:Bert Mar 30th 10:16 pmYes, these dimensions correspond to the discussion in the article.
Bert
Quote:Brynetan Mar 22nd 8:24 pmDear all,
I've started learning about plane-wave DFT last month. My goal is to perform density of state calculations so I tried out the following NWChem example : http://www.nwchem-sw.org/index.php/Plane-wave_Density_Functional_Theory#Using_BAND_to_Calculate_the_Density_of_States_of_Diamond. The diamond-dos.dos was created in the perm directory. I've figured out that the first column of this file gives the energy in Hartree units and the second column is the density of states(DOS) and thus was able to generate the DOS plot that looks identical to the one on the web page. However, I have been trying unsuccessfully to find the units of the DOS. Firstly, is the latter defined as the number of one-electron states divided by the energy range (E,E+delta_E)/delta_E (cf. "SOLID STATE PHYSICS" by Ashcroft and Mermin)? If so what are the units of the one-electron energies?
Secondly, can anyone tell me what the field "np_dimensions" is? According to "Hard scaling challenges for ab initio molecular dynamics in NWChem:Using 100,000 cpus per second", np stands for the number of processors and npi/npj stands for the size of column(row) processor group. In NWChem, the directive is given as NP_DIMENSIONS <integer npi npj default -1 -1>. Do they correspond to the ones in the article? Lastly, the Nickel example gives the following input: np_dimensions -1 -1 4. What does 4 represent?
Thank you very much for your help.
Regards,
Bryne |
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| 6:40:50 PM PDT - Wed, Apr 11th 2012 |
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| Thank you for the clarification, Bert.
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| 9:45:48 PM PDT - Sun, Apr 29th 2012 |
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Projected density of states(PDOS)
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Dear all,
According to http://www.emsl.pnl.gov/docs/nwchem/nwchem-support/2006/02/0054.RE:_NWCHEM_New_NWPW_features_in_NWChem_4, alpha corresponds to the width of the Lorentzian function. Can anyone tell me the purpose of varying this width? My initial guess would be that it is used to model the bulk DOS from that obtained from the unit cell.
Please advise. Thank you for your help.
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