[Wien] Effect of finite nucleus on the change of electron capture decay rate under compression

[Pavel Novak]

Dear colleagues,

I still can dig out the program, though we did not use it for years. It 
worked fine for Fe, but not for Gd and it failed for lighter nuclei. 
I am rather busy  this week, but I'll respond at the end of month.

Pavel Novak

On Tue, 21 Jan 2014, Laurence Marks wrote:

> A relevant paper may be http://yclept.ucdavis.edu/Publ/Bhf_SIC.pdf
> 
> Novak et al, PHYSICAL REVIEW B 67, 140403R, 2003.
> 
> N.B., if anyone has the code please send it to me -- I will keep a
> copy (I thought I had it). Maybe it should be part of the unsupported
> software.
> 
> On Tue, Jan 21, 2014 at 7:05 AM, Peter Blaha
> <pblaha at theochem.tuwien.ac.at> wrote:
> > I don't have this SIC code, which gave better hyperfine fields for Fe
> > (but failed miserable for another test, so it might have been accidentally).
> >
> > Anyway, yes, try also LDA, as GGAs may behave strange at the nucleus.
> >
> > On 01/21/2014 01:56 PM, Laurence Marks wrote:
> >> Interesting.
> >>
> >> Maybe relevant, maybe not. I seem to remember that conventional
> >> functionals do not always do a great job near the nucleus, so there can
> >> be errors in the high angle x-ray scattering factors. Some time ago
> >> there was an experimental lcore which did a better job; unfortunately I
> >> cannot find the reference. Peter probably has the code and, at your own
> >> risk, you might want to try it.
> >>
> >> Beyond that you would have to change the nuclear part of the Coulomb
> >> integrals in lapw0.F.
> >>
> >> ______________________________
> >> Laurence Marks
> >> Dept Mat Sci & Eng
> >> Northwestern University
> >> www.numis.northwestern.edu <http://www.numis.northwestern.edu>
> >> 847 491 3996
> >>
> >> On Jan 21, 2014 4:31 AM, "Amlan Ray" <amlan_ray2005 at yahoo.com
> >> <mailto:amlan_ray2005 at yahoo.com>> wrote:
> >>
> >>     I tried different values of R0 (R0=0.0001 BU, 0.00001 BU, 0.00004
> >>     BU) for calculating the electron density at the nucleus. Of course,
> >>     the electron density changes for different values of R0 and so the
> >>     predicted electron capture rate also changes. However I am not
> >>     trying to compare the calculated electron capture rate with the
> >>     experimental result. By taking a suitable average over R0, I can
> >>     probably get a good agreement between WIEN2K calculation and the
> >>     experimental result. However I am interested to calculate the rate
> >>     of increase of the electron density at the nucleus under
> >>     compression. As I compress 7BeO lattice, the fractional change of
> >>     the electron density at the nucleus (Delta_Lambda/Lambda) increases
> >>     linearly with the applied external pressure. This result was
> >>     obtained from both WIEN2K calculations and experiment. However the
> >>     slope of the staright line (Delta_Lambda/Lambda versus Pressure
> >>     plot) is very different for WIEN2K calculation and experimental
> >>     result. From WIEN2K calculation, I get
> >>     K_P=0.42X10^-4 (GPa)^-1, whereas expt result is K_P=(2.2+-0.1)X10^-4
> >>     (GPa)^-1. The calculated value of K_P is essentially independent of
> >>     R0. I tried different values of R0 and do not find any change in the
> >>     calculated value of K_P. So naturally taking average over R0 will
> >>     not change K_P. It is very robust. However the consideration of a
> >>     finite nucleus will change the character of the wave function ( both
> >>     radial and Z-dependence) within the nuclear volume. So I think the
> >>     consideration of a finite nucleus will change the calculated value
> >>     of K_P and it should increase the value bringing it closer to the
> >>     experimental number.
> >>     Isomer shift is not directly proportional to the electron density at
> >>     the nucleus and people tune the calculations using experimental
> >>     results. In the case of isomer shift, I am interested to know
> >>     how well WIEN2K calculations agree with the change of isomer shift
> >>     under compression. Please refer me to a suitable publication where
> >>     the change of isomer shift under compression has been studied.
> >>     With best regards
> >>     Amlan Ray
> >>     VECC, Kolkata
> >>     India
> >>
> >>
> >>
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> >>
> >
> > --
> >
> >                                        P.Blaha
> > --------------------------------------------------------------------------
> > Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
> > Phone: +43-1-58801-165300             FAX: +43-1-58801-165982
> > Email: blaha at theochem.tuwien.ac.at    WWW:
> > http://info.tuwien.ac.at/theochem/
> > --------------------------------------------------------------------------
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> 
> 
> 

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