Re: [Phonopy-users] [**SPAM?**] Re: [**SPAM?**] Re: [**SPAM?**] Re: phonon energy
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From: Shilendra K. S. <sh...@ii...> - 2017-07-29 09:18:49
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Dear Roginskii Eugene, Thank you for clarifying my doubt, I will read much more about phonon energy and try to simulate Raman Spectra. Shilendra > The first thing you have to do when meet unknown term is to search for > the literature. > Finally I've found the primary paper describes the term DOI: > 10.1016/j.jlumin.2005.03.011 > quote from the paper: " Raman spectroscopy of undoped NaYF4 is presented > here for the first time, demonstrating that the dominant phonon modes in > NaYF4 lie between 300 and 400 cm-1. The fact that these phonon modes are > also the optically active ones is further > demonstrated by temperature-dependent excitation spectroscopy." > > There is no connection with DOS as I supposed. > > So phonon energy term means the highest energy of phonon which is Raman > active and obtains a high Raman intensity (as far I understood). To > simulate Raman spectra with ABINIT by finite-displacement method I would > suggest to use my python script (follow by > https://github.com/ladyteam/ramanpy beta version). Try to find > alternative for VASP calculator. > > But anyway, the phonon-energy always below the edge of the higher part > of DOS ~240cm-1 in your case. > > Eugene. > > On 07/29/2017 12:59 AM, Shilendra Kumar Sharma wrote: >> Dear Roginskii Eugene , >> >> Actually, I am studying lanthanide doped luminescent materials in which >> host matrix should have low phonon energy to minimize non-radiative >> losses >> (link herein). >> >> http://pubs.rsc.org/-/content/articlepdf/2014/ta/c4ta04274c >> >> On the theoretical bases I want to see which host matrix has low phonon >> energy. As it is written in this paper NaYF4 has low phonon energy (ca. >> 360 cm-1). Such phonon energy I want to calculate for other matrix. >> >> >> Thank You >> >> Shilendra >> >> >>> Hi, >>> Your question is out of scope of PHONOPY. And truly saying I don't >>> understand what does your phonon energy means, do I can't answer. I can >>> only recall, that phonon is a quasi-particle which determined by energy >>> (eigenvalue of dynamical matrix) and atomic displacements (eigenvector >>> of >>> dynamical matrix) both depends on k-vector. The number of phonons in >>> the >>> periodic structure depends on number of atoms in unit cell e.g. 3N. >>> This >>> set may include double and/or triple degenerate modes, due to symmetry >>> selection rules. The maxima in DOS usually hard to explain >>> unambiguously, >>> some are due to high concentration of phonons in the energy region some >>> due to crossing of phonon branches. It make scene after plotting of >>> band >>> structure. >>> >>> If you want to calculate Harmonic phonon energy you're better study >>> PHONOPY formulations on thermodynamic properties >>> https://atztogo.github.io/phonopy/formulation.html#thermodynamic-properties >>> >>> and run the calculations with proper setup. Below is example how to >>> create >>> thermal_properties.yaml file: >>> phonopy --mp="41 41 41" -t --dim="2 2 2" --tmax=2004 --tstep=2 -c >>> POSCAR >>> >>> Good luck, >>> Eugene >>> >>> >>> On 07/28/2017 04:28 PM, Shilendra Kumar Sharma wrote: >>> >>> Dear Roginskii Eugene thank you for your reply ! >>> >>> I am using VASP+Phonopy for phonon calculation. As you suggested >>> conversion factor for vasp. >>> >>> I gave command "phonopy -p --dos --factor=521.47 mesh.conf" for phonon >>> DOS >>> calculation. Now my frequencies are in cm-1. >>> >>> I have attached here my dos plot and from DOS plot maximum frequency >>> will >>> be my phonon energy which I am getting 250 cm-1. >>> >>> Am I understanding right ? >>> If I am wrong, please correct me! >>> >>> >>> Thank You >>> >>> Shilendra >>> >>> >>> >>> >>> >>> >>> >>> >>> Hi, if you using VASP calculator use --factor=521.45 option. In case of >>> ABINIT use --factor=716.851928469, the value calculates as multiply of >>> factors: >>> #Abinit_units to THZ= 21.4906801658 >>> #THZ to CM-1=33.356410 >>> >>> On 07/28/2017 04:52 AM, Shilendra Kumar Sharma wrote: >>> >>> >>> Dear All phonopy users, >>> >>> How does calculate phonon energy for any system in cm-1 ? I am doing >>> phonon calculation with VASP+phonopy combination. I have calculated >>> phonon >>> DOS and band structure. Now I want to calculate phonon energy (cm-1) >>> for >>> my system. How can I know or calculate phonon energy for my compound >>> from >>> phonon calculation. >>> >>> >>> Thank You All >>> >>> Shilendr >>> >>> ------------------------------------------------------------------------------ >>> Check out the vibrant tech community on one of the world's most >>> engaging tech sites, Slashdot.org! http://sdm.link/slashdot >>> _______________________________________________ >>> Phonopy-users mailing list >>> Pho...@li...<mailto:Pho...@li...> >>> https://lists.sourceforge.net/lists/listinfo/phonopy-users >>> >>> >>> >>> >>> ------------------------------------------------------------------------------ >>> Check out the vibrant tech community on one of the world's most >>> engaging tech sites, Slashdot.org! http://sdm.link/slashdot >>> _______________________________________________ >>> Phonopy-users mailing list >>> Pho...@li...<mailto:Pho...@li...> >>> https://lists.sourceforge.net/lists/listinfo/phonopy-users >>> >>> >>> >>> >>> >>> ------------------------------------------------------------------------------ >>> Check out the vibrant tech community on one of the world's most >>> engaging tech sites, Slashdot.org! http://sdm.link/slashdot >>> >>> >>> >>> _______________________________________________ >>> Phonopy-users mailing list >>> Pho...@li...<mailto:Pho...@li...> >>> https://lists.sourceforge.net/lists/listinfo/phonopy-users >>> >>> >>> ------------------------------------------------------------------------------ >>> Check out the vibrant tech community on one of the world's most >>> engaging tech sites, Slashdot.org! >>> http://sdm.link/slashdot_______________________________________________ >>> Phonopy-users mailing list >>> Pho...@li... >>> https://lists.sourceforge.net/lists/listinfo/phonopy-users >>> >> >> ------------------------------------------------------------------------------ >> Check out the vibrant tech community on one of the world's most >> engaging tech sites, Slashdot.org! http://sdm.link/slashdot >> _______________________________________________ >> Phonopy-users mailing list >> Pho...@li... >> https://lists.sourceforge.net/lists/listinfo/phonopy-users > > > ------------------------------------------------------------------------------ > Check out the vibrant tech community on one of the world's most > engaging tech sites, Slashdot.org! http://sdm.link/slashdot > _______________________________________________ > Phonopy-users mailing list > Pho...@li... > https://lists.sourceforge.net/lists/listinfo/phonopy-users > |