WIEN2k-FAQ: "x lapw2 -qtl" crashes

©2001 by P. Blaha, K. Schwarz and J. Luitz

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In some cases it may happen that you cannot calculate the case.qtl file used for a DOS calculation. x lapw2 -qtl crashes with:

Input/Output Error 148: Invalid character
   In Procedure: outp
        At Line: 181
      Statement: Formatted READ
           Unit: 1010
   Connected To: ./phos.help040
           Form: Formatted
         Access: Sequential
Records Read   : 34

This info tells you, that a "QTL-B"-value was so large, that it could not be printed properly with the corresponding FORMAT to case.helpXXX; but instead "*****" where printed. When subroutine outp tries to read this file, a crash occurs. Usually this happens when you try to calculate the DOS (partial charges Q_tl) up to high energies.

In any case, if the error is in case.help040, it would tell you that the problem is connected with the energy parameters of atom 10 (file 31 corresponds to atom 1, .....). View this file and check line 34 ("Records Read"). It will contain the "*****" mentioned above and from this line you will know for which "l" (angular momentum) and for which eigenvalue (energy) the crash happens.

Edit case.in1 and either reduce EMAX (if you are interested only in the occupied DOS and the "bad" eigenvalue is at higher energies) or change the energy-parameter of the corresponding atom and angular momentum (usually set it to a higher energy). Eventually you need to add additional LOs (at high energy (sometimes 5 Ry or so) or increase the energy seperation between LO and L/APW energies.

Peter Blaha,