maybe you could provide the input file for further check Giovanni > On 18 Mar 2021, at 14:34, Offermans Willem <[email protected]> wrote: > > Hi Giovanni and Quantum Espresso friends, > > > Thank you for your response. It is very much appreciated. > > You are right, by specifying the unit cell in the following > way, the warning message disappeared. > > <snip> > ... > ibrav = 8 > celldm(1) = 10.6279 > celldm(2) = 1.5 > celldm(3) = 4.5961940777125589086 > … > </snip> > > Though, I specified the cell dimensions in Bohr units, but this is > just a detail for this communication. > > As bonus, I can now find the following in the output: > > <snip> > ... > point group C_i (-1) > there are 2 classes > the character table: > > E i > A_g 1.00 1.00 > A_u 1.00 -1.00 > > the symmetry operations in each class and the name of the first element: > > E 1 > identity > i 2 > inversion > … > </snip> > > I wonder whether this is compatible to the following output, obtained in the > old fashioned way. > > <snip> > ... > Found symmetry operation: I + ( -0.5000 0.0000 -0.0000) > This is a supercell, fractional translations are disabled > Message from routine find_sym: > Not a group! Trying with lower acceptance parameter... > Message from routine find_sym: > Symmetry operations form a group > … > </snip> > > The last line says: "Symmetry operations form a group”. > Great, which group is it? > > > > Met vriendelijke groeten, > Mit freundlichen Grüßen, > With kind regards, > > > Willem Offermans > Researcher Electrocatalysis SCT > VITO NV | Boeretang 200 | 2400 Mol > Phone:+32(0)14335263 Mobile:+32(0)492182073 > > [email protected] <mailto:[email protected]> > <vito.jpg> > >> On 18 Mar 2021, at 10:13, Giovanni Cantele <[email protected] >> <mailto:[email protected]>> wrote: >> >> Here, a list of the ibrav values that you can choose >> https://www.quantum-espresso.org/Doc/INPUT_PW.html#idm200 >> <https://eur02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.quantum-espresso.org%2FDoc%2FINPUT_PW.html%23idm200&data=04%7C01%7C%7C7db3d1168d674e9bc47b08d8e9ee7e1a%7C9e2777ed82374ab992782c144d6f6da3%7C0%7C1%7C637516557853981073%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=6NM1WCXt2ogavB5wbKfDwv1wmeybmvhrmyyh2PPpEnM%3D&reserved=0> >> >> It seems that you have a simple orthorhombic lattice, that should correspond >> to ibrav = 8. >> Than you can specify the variables >> a >> b >> c >> as crystal axes lengths in Angstrom units. >> >> Giovanni >> >> >>> On 18 Mar 2021, at 10:03, Offermans Willem <[email protected] >>> <mailto:[email protected]>> wrote: >>> >>> >>> Dear Quantum Espresso friends, >>> >>> In most of my calculations, I’m dealing with metallic slabs, representing >>> surfaces, derived from fcc metals, such as (221) or (533). >>> >>> In these calculations, I’m dealing with structures with symmetry. >>> The single symmetry element is an inversion center. S_2 is the Schönfließ >>> symbol, >>> if I recall correctly. >>> >>> In the output file of pw.x, I encounter the following note: >>> >>> <snip> >>> ... >>> Message from routine setup: >>> using ibrav=0 with symmetry is DISCOURAGED, use correct ibrav instead >>> … >>> </snip> >>> >>> The unitcell is defined as: >>> >>> <snip> >>> ... >>> celldm(1)= 10.627880 celldm(2)= 0.000000 celldm(3)= 0.000000 >>> celldm(4)= 0.000000 celldm(5)= 0.000000 celldm(6)= 0.000000 >>> >>> crystal axes: (cart. coord. in units of alat) >>> a(1) = ( 1.000000 0.000000 0.000000 ) >>> a(2) = ( 0.000000 1.500000 0.000000 ) >>> a(3) = ( 0.000000 0.000000 4.596194 ) >>> … >>> </snip> >>> >>> I would like to follow the advice to use the correct ibrav, but I need some >>> help >>> to determine the correct ibrav. >>> >>> Can someone help me to determine the correct Ibrav? >>> >>> >>> >>> >>> >>> Met vriendelijke groeten, >>> Mit freundlichen Grüßen, >>> With kind regards, >>> >>> >>> Willem Offermans >>> Researcher Electrocatalysis SCT >>> VITO NV | Boeretang 200 | 2400 Mol >>> Phone:+32(0)14335263 Mobile:+32(0)492182073 >>> >>> [email protected] <mailto:[email protected]> >>> <vito.jpg> >>> >>> _______________________________________________ >>> Quantum ESPRESSO is supported by MaX (www.max-centre.eu >>> <https://eur02.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.max-centre.eu%2F&data=04%7C01%7C%7C7db3d1168d674e9bc47b08d8e9ee7e1a%7C9e2777ed82374ab992782c144d6f6da3%7C0%7C1%7C637516557853981073%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=jeXusjjvfJN0lou7Zw6kWF3IfT%2FHlfAnrhScrKK5XZM%3D&reserved=0>) >>> users mailing list [email protected] >>> <mailto:[email protected]> >>> https://lists.quantum-espresso.org/mailman/listinfo/users >>> <https://eur02.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.quantum-espresso.org%2Fmailman%2Flistinfo%2Fusers&data=04%7C01%7C%7C7db3d1168d674e9bc47b08d8e9ee7e1a%7C9e2777ed82374ab992782c144d6f6da3%7C0%7C1%7C637516557853991067%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=DIWxANaPk7CwK2JTNWRbrE1WYoyMuWxw6SLBRxijG%2B0%3D&reserved=0> >> -- >> >> Giovanni Cantele, PhD >> CNR-SPIN >> c/o Dipartimento di Fisica >> Universita' di Napoli "Federico II" >> Complesso Universitario M. S. Angelo - Ed. 6 >> Via Cintia, I-80126, Napoli, Italy >> e-mail: [email protected] <mailto:[email protected]> >> Phone: +39 081 676910 >> Skype contact: giocan74 >> >> ResearcherID: http://www.researcherid.com/rid/A-1951-2009 >> <http://www.researcherid.com/rid/A-1951-2009> >> Web page: https://sites.google.com/view/giovanni-cantele/home >> <https://eur02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fsites.google.com%2Fview%2Fgiovanni-cantele%2Fhome&data=04%7C01%7C%7C7db3d1168d674e9bc47b08d8e9ee7e1a%7C9e2777ed82374ab992782c144d6f6da3%7C0%7C1%7C637516557853991067%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=3LwrKsdaE9ol%2BicjrppzmUrVfumjyQ%2BOw%2Bm%2FAd2fIMo%3D&reserved=0> >> _______________________________________________ >> Quantum ESPRESSO is supported by MaX (www.max-centre.eu >> <http://www.max-centre.eu/>) >> users mailing list [email protected] >> <mailto:[email protected]> >> https://lists.quantum-espresso.org/mailman/listinfo/users >> <https://lists.quantum-espresso.org/mailman/listinfo/users> > _______________________________________________ > Quantum ESPRESSO is supported by MaX (www.max-centre.eu) > users mailing list [email protected] > https://lists.quantum-espresso.org/mailman/listinfo/users
-- Giovanni Cantele, PhD CNR-SPIN c/o Dipartimento di Fisica Universita' di Napoli "Federico II" Complesso Universitario M. S. Angelo - Ed. 6 Via Cintia, I-80126, Napoli, Italy e-mail: [email protected] Phone: +39 081 676910 Skype contact: giocan74 ResearcherID: http://www.researcherid.com/rid/A-1951-2009 Web page: https://sites.google.com/view/giovanni-cantele/home
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