       Re: Cross sections calculations

• To: mathgroup at smc.vnet.net
• Subject: [mg74039] Re: [mg74009] Cross sections calculations
• From: "Chris Chiasson" <chris at chiasson.name>
• Date: Wed, 7 Mar 2007 03:11:24 -0500 (EST)
• References: <200703050956.EAA20887@smc.vnet.net>

```you might try resending the data as comma separated values (csv) -- it
didn't come out right over here

On 3/5/07, Johan Mars <jmars at uwc.ac.za> wrote:
> Dear mathgroup
> I am new to math 5.1 and like assistance solving the calculations for
> cross sections
> I am using (...r-matrix approach---------
>  parameters: y is cross section, x is energy and t is the angle (in
> degrees). The summation of l is from 0 to n=7.
> sqrt is the square root. Pl is the cosine of the Legendre polynomial.
> j=t/2 and
> u=-2.15*ln(sin(j))...)
>
> the equation which is:
>
> y=1+3.4*x*sin^4(j)*[sum(
> Bl*Pl)]+[1.86*sqrt(x)*sin^2(j)*(sum(Tl*Pl*cos(u))-sum(Rl*Pl*sin(u))]
>
> Bl, Tl and Rl are unknowns to be calculated from the fit to the data.
> This means that 3 sets of data (2D vectors (x and y)) are needed for
> the determination.
> I have added the data points since I do not have a site on the web to
> place them.
>
> t=85.7
> t=123.8                                                t=152.6
> -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
>         x                     y                                      x
>          y                                                        x
>            y
> -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
>   1.032919        1.342186                               1.034540
> 1.638148                                  1.035617        1.676251
>
>   1.038439        1.342024                                1.039728
>  1.588318                                 1.040366        1.589682
>
>   1.043274        1.341003                                1.044800
>  1.508356                                 1.045648        1.502952
>
>   1.045025        1.333919                                1.047154
>  1.296485                                 1.050777        1.398026
>
>   1.046472        1.308382                                1.048602
>  1.256833                                 1.053271        1.950580
>
>   1.048490        1.308323                                1.049745
>  1.208223                                 1.054043        3.166415
>
>   1.049061        1.300394                                1.050890
>  1.219943                                 1.054630        3.582741
>
>   1.049898        1.282787                                1.051602
>  1.651101                                 1.055846        3.561088
>
>   1.051612        1.255484                                1.052843
>  1.994618                                 1.056856        3.159478
>
>   1.053020        1.277421                                1.054796
>  2.769292                                 1.058560        2.991751
>
>   1.054315        1.349470                                1.055800
>  2.965068                                 1.059078        2.648054
>
>   1.055076        1.384613                                1.057125
>  2.777640                                 1.060705        2.428667
>
>   1.058312        1.440782                                1.058296
>  2.563109                                 1.063215        2.452225
>
>   1.060216        1.425781                                1.060041
>  2.375554                                 1.065260        2.241832
>
>   1.062424        1.424837                                1.062594
>  2.314452                                 1.070995        2.100240
>
>   1.064442        1.421262                                1.064609
>  2.178097                                 1.076282
> 2.147275
>   1.068439        1.419386                                1.069947
>  2.073923
>   1.073883        1.419227                                1.075099
>  2.066335
>   1.077386        1.405058
>
>
> Please note that in literature various other symbols are used for the
> cross sections, the energies and angles. Mine here are just for
> simplicity.
> I hope to hear from you soon. Thanks a million.
>
>
>
> Sincere regards
>
> Johan Mars, Dr
> Environmental Awareness         Tel.: +27 21 9593050
> Department of Chemistry             Fax.: +27 21 9593055
> University of the Western Cape     Cell.:+27 72 5043585
> Private Bag X17
> Bellville, 7535
> South Africa
> http://www.uwc.ac.za
>
>

--
http://chris.chiasson.name/

```

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