# STM charge density

**URL:** <https://discourse.abinit.org/t/stm-charge-density/3778>\
**Category:** Ground state\
**Created:** [November 10, 2025, 5:54pm UTC](https://discourse.abinit.org/t/stm-charge-density/3778 "2025-11-10T17:54:22Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![rajeshatpsi](https://discourse.abinit.org/letter_avatar_proxy/v4/letter/r/34f0e0/32.png) [@rajeshatpsi](https://discourse.abinit.org/u/rajeshatpsi)\
**Post date:** [November 10, 2025, 5:54pm UTC](https://discourse.abinit.org/t/stm-charge-density/3778/1 "2025-11-10T17:54:22Z")

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Hi,

I was trying to run this tutorial [https://docs.abinit.org/tests/v4/Input/t46.abi](https://docs.abinit.org/tests/v4/Input/t46.abi) regarding stm charge density of Al.

It gives an error for dataset4 saying: _chkint\_prt: ERROR -  
The value of the input variable prtstm is -6, while it must be  
larger or equal to 0.  
Action: you should change the input variable prtstm._

Another problem I encountered when I worked on the first three dataset and increased _nstep_ 1 to 10 for data set 2 and 3 since with _nstep=1_ was not enough SCF cycles to converge. It gives an error: _chkint\_prt: ERROR -  
Context: the value of the variable nstep is 10.  
The value of the input variable prtstm is 1, while it must be  
equal to 0  
Action: you should change the input variables prtstm or nstep._

Any help!

P.S. Can I use toldfe instead of tolwfr for GS optimization?

Thanks!

Rajesh

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**Author:** ![bguster](https://discourse.abinit.org/letter_avatar_proxy/v4/letter/b/ac8455/32.png) [@bguster](https://discourse.abinit.org/u/bguster)\
**Post date:** [November 28, 2025, 9:44am UTC](https://discourse.abinit.org/t/stm-charge-density/3778/2 "2025-11-28T09:44:27Z")

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Hi Rajesh,

Q1: Are you using the same pseudo as in the test input file?

Q2: in the 2nd and 3rd dataset there is no need for a further convergence of the wavefunction. Abinit simply reads the one converged in the first dataset.

Bogdan

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**Author:** ![rajeshatpsi](https://discourse.abinit.org/letter_avatar_proxy/v4/letter/r/34f0e0/32.png) [@rajeshatpsi](https://discourse.abinit.org/u/rajeshatpsi)\
**Post date:** [November 28, 2025, 5:28pm UTC](https://discourse.abinit.org/t/stm-charge-density/3778/3 "2025-11-28T17:28:47Z")

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Hi Bogdan,

I am using exactly the same pseudo provided in the tutorial folder.

Thanks,

Rajesh