From 348040fcfb46b7cf7ec9d25e285a467b2e8e6482 Mon Sep 17 00:00:00 2001
From: edoapra <edoardo.apra@gmail.com>
Date: Mon, 29 Nov 2021 12:45:47 -0800
Subject: [PATCH] stop when  velocities=0 to avoid 1/(E_kin=0)

---
 src/qmd/qmd_fix_momentum.F | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/qmd/qmd_fix_momentum.F b/src/qmd/qmd_fix_momentum.F
index 5950227fff..198381029f 100644
--- a/src/qmd/qmd_fix_momentum.F
+++ b/src/qmd/qmd_fix_momentum.F
@@ -142,6 +142,12 @@ c      make sure center-of-mass velocity is still zero
       end if
 c     calculate current kinetic energy
       call qmd_kinetic(n,m,v,KE_after)
+      if(KE_after.lt.1d-12) then
+       if(ga_nodeid().eq.0)
+     C        write(luout,*)
+     C        ' zero velocities after removal of roto-translations'
+       call errquit(' zero Kinetic Energy',0,GEOM_ERR)
+      endif
 c     rescale velocities to match kinetic energy on entry
       call qmd_rescale(n,m,v,KE_after,KE_in)
 c