Subject: Summary: Frozen calculation in Gaussian

From: ��Ѹ�� <[email-masked]>
Date: Fri, 16 May 2003 15:54:51 +0800

Dear CCls：

	With the help of Jim Hess and Cheers Martijn , here are some ways to
	do frozen calculations in Gaussian.
	
    1.Frozing one atom:
      Write 0 or -1 between the atom center label and the coordinates. -1 for frozen 
	  and 0 for not-frozen.Like this:
	_____________________________________________________
	#rhf/sto-3g opt nosymm test

     silly chemistry, but for illustrative purposes...

     0,1
     8  0       -1.000000    0.000000    0.000000
     6 -1        0.000000    1.000000    0.000000
     6 -1        0.000000   -1.000000    0.000000
     8  0        1.000000    0.000000    0.000000

	______________________________________________________　　
	
	2.Frozing only specific coordinates(e.g. z-coordinate only).
  	Use symbolic cartesian coordinates and set "opt=z-matrix" .
	The coordinates to be frozen are flagged with an "F" in the 
    "Variables:" section.Like this:
	___________________________________________
	#rhf/sto-3g opt=(z-matrix) test

     symbolic cartesian optimization

		0,1
		O1 0 x1  y1  z1
		C2 0 x2  y2  z2
		C3 0 x3  y3  z3
		Variables:
		x1=-1.
		y1=0.
		z1=0.
		x2=0. 
		y2=1. 
		z2=0. F
		x3=0.
	    y3=1.
	    z3=1. F
	
	____________________________________________
	
    3. Use internal coordinates, in the constant section set the frozen item. 
	Like this(the angle will be frozen):
	___________________________________________ 
	#rhf/sto-3g opt=(z-matrix) test

     internal coordinates

		0,1
		C1 
		O2  C1  r1
		C3  O2  r1  C1 angle 
		Variables:
		r1=1.5
	    constant
	    angle=60.0  
	
    ____________________________________________
	
	4. Use ModRedun. Like this(the angle will be frozen):
	___________________________________________________
	#rhf/sto-3g Opt=ModRedun 

	ModRedun test

		0,1
		C1 
		O2  C1  r1
		C3  O2  r1  C1 angle 
		Variables:
		r1=1.5
	    angle=60.0  
	    ModRedun
        3 2 1 60.0   F
	
	_____________________________________________________
     One cannot include dummy atoms as part of a constrained coordinate 
     when performing optimizations in redundant internal coordinates.

    Thank you for your help!　　　　　　　　
 				
　　　　　　　　　　　　　　Ding Xunlei
　　　　　　　　　　　　　　2003-05-16
______________________________________________
Ding Xunlei, Ph.D. Candidate
Open Laboratory of Bond Selective Chemistry
University of Science & Technology of China
Hefei, Anhui 230026, P.R.China
Tel.: 0086-551-3603418
Fax.: 0086-551-3602969
E-mail: [email-masked]
Http://www.bsc.ustc.edu.cn/~dxl