Subject: G94: UNITS in SCAN

From: [email-masked] (Dr Lutz Ackermann)
Date: Wed, 4 Dec 1996 16:12:10 GMT

Hello CCL'ers

Gaussian 94' s  SCAN function causes me some headache. The way, units for the stepsize
are interpreted seems to be rather unpredictable. For example, I ran two rather similar
jobs (see below) in which g94 acts stunningly different:

************************************** job1.log ****************************
       Variables:
 zCe                  -0.162   0         0.     
 R1                    2.27    2         0.05   
 A1                  142.      2         3.   
 Scan the potential surface.
 Variable   Value     No. Steps Step-Size
  -------- ----------- --------- ---------
    2       2.270000       2      0.0500
    3     142.000000       2      3.0000
 A total of      9 points will be computed.
  
  ...

 Scan completed.

  Summary of the potential surface scan:
     N      R1         A1          HF     
   ----  ---------  ---------  -----------
      1     2.2700   142.0000 -10610.64422
      2     2.3200   142.0000 -10610.64868
      3     2.3700   142.0000 -10610.64848
      4     2.2700   145.0000 -10610.65709
      5     2.3200   145.0000 -10610.66256
      6     2.3700   145.0000 -10610.66329
      7     2.2700   148.0000 -10610.64848
      8     2.3200   148.0000 -10610.65383
      9     2.3700   148.0000 -10610.65413
   ----  ---------  ---------  -----------

************************************** job1.log ****************************
************************************** job2.log ****************************
       Variables:
 zCe                  -0.162   0         0.     
 R1                    2.353   0         0.05   
 A1                  144.      1         2.     
 Scan the potential surface.
 Variable   Value     No. Steps Step-Size
 -------- ----------- --------- ---------
    3     144.000000       1    114.5916
 A total of      2 points will be computed.

 ...

  Scan completed.

   Summary of the potential surface scan:
      N      A1          HF     
    ----  ---------  -----------
       1   144.0000 -10610.66100
       2   258.5916 -10609.94079
    ----  ---------  -----------

    ...
************************************** job2.log ****************************

In the first case, both the initial value of the angle A1 as well as the step size
are being interpreted in degree (which corresponds to the default, according to the
manual).

In the second case however, only the initial value of the angle A1 is treated as degrees
whereas the stepsize is taken in radians (yielding nonsentic geometries, of course).

Has anyone encountered simmilar erratic behaviour? Is ther a way to force G94 to interprete
both the initial value and the step size consistently as degrees?

Thanks a lot,

Cheers, Lutz.

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               <    Dr. Lutz Ackermann                        >
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