When NR kicks in a large step causes SCF convergence to fail, presumably because of a bad guess. I tried to decrease DXMAX to 0.001, but there seems to be no effect on when NR starts.
Is there a better way to delay or prevent switching to NR? Alternatively, is there a way to reduce the NR step size?
Below is an example of the step when NR starts:
MAXIMUM GRADIENT = 0.0462724 RMS GRADIENT = 0.0142135 FORCE CONSTANT MATRIX NOT UPDATED --- TAKING FIRST STEP MIN SEARCH, CORRECT HESSIAN, TRYING PURE NR STEP NR STEP HAS LENGTH = 92.651197 TRIM/QA LAMBDA FOR NON-TS MODES = -84.40598785 TRIM/QA STEP HAS LENGTH = 0.001000 RADIUS OF STEP TAKEN= 0.00100 CURRENT TRUST RADIUS= 0.00100 TRANSFORMING DISPLACEMENT FROM INTERNALS TO CARTESIANS THE ROOT MEAN SQUARE ERROR IN ITERATION 1 IS 0.00000001 THE ROOT MEAN SQUARE ERROR IN ITERATION 2 IS 0.00000000 MAX PRIMITIVE INTERNAL COORDINATE DEVIATION IS 0.00000000 INTERNAL COORDINATES SELF-INCONSISTENCY IS 0.00000303