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Calcite anyone?
Posted: Thu Mar 26, 2020 3:47 pm
by Tunneller
Pilikgos et al have published a Hamiltonian for Calcite in "Sign and Magnitude of Spin Hamiltonian Parameters for
Mn2+ Impurities in Calcite. A Multi- and Low-Frequency Study" . It seems like EasySpin Pepper has all of the functionality
but I'm confused how to add the ligand terms O^0_4 and O^3_4. I see there are extended Steven's operators with the command
stev
but I can't work out it works. I wonder if maybe someone has coded this Hamiltonian already or if not any pointers? Thanks, T.
- PictureHal.png (136.2 KiB) Viewed 3760 times
Re: Calcite anyone?
Posted: Thu Mar 26, 2020 3:54 pm
by Stefan Stoll
Sys.B4 = [0 B43 0 0 B40 0 0 0 0];
Re: Calcite anyone?
Posted: Thu Mar 26, 2020 4:54 pm
by Tunneller
Wow thanks Stefan that was fast.
For the nuclear quadrupole term, the paper references
PD = −0.176(12)· 10−4 cm−1 , PE = 0.13(5) · 10−4 cm−1
and defines the corresponding Hamiltonian as
PD [ Iˆ2 z – 1/3 I(I + 1) ]+ PE ( Iˆ 2 x − Iˆ 2 y )
So I think I can do Qxx = PE-PD/3, Qyy = -PE-PD/3, Qzz = 2*PD/3 , define Sys.Q = [Qxx Qyy Qzz] and multiply by 2.998 to get MHz. yes?
Lastly, he has a nuclear Zeeman term
− µN gN [ Iˆx Bx + Iˆy By + Iˆz Bz ]
gN = +1.38(5) cm−1
is there a keyword?
Regards
Code: Select all
c = 2.998;
Sys.S = 5/2;
Sys.lw = 1;
gperp = 2.00123;
gtang = 2.00131;
Sys.g = [gperp gtang];
Aperp = -88.23*c;
Atang = -87.6*c;
Sys.A = [Aperp Atang];
%
% ZFS terms
%
Sys.B4 = [0 1.12 0 0 -0.047 0 0 0 0]* c; %B34 and B04 terms only
Sys.D = -76.0 * c; %consider adding Dstrain
Sys.E = 0; % consider adding Estrain
%
% Nuclear Quadrupole
%
PD = -0.176*c;
PE = 0.13*c;
Qxx = PE - PD/3;
Qyy = -PE - PD/3;
Qzz =2*PD/3;
Sys.Q = [Qxx Qyy Qzz];
%
% Nuclear zeeman?
%
gN = 1.38;
%
% Spectrometer settings
%
Exp.mwFreq = 9.4;
Exp.Range = [270 400];
Seems about correct
Re: Calcite anyone?
Posted: Thu Mar 26, 2020 8:14 pm
by Stefan Stoll
Re: Calcite anyone?
Posted: Fri Mar 27, 2020 9:15 am
by Tunneller
I needed to add Sys.Nucs = '55Mn' and then it ran great.
- Picture2.png (21.68 KiB) Viewed 3748 times
Looks just like the literature, and just like what I get from Bruker too. Simple pleasures
Ok, now next step is to understand broadening. What I read is that as the manganese percentage in the crystal increases, then the lines broaden.
Regards, John
Re: Calcite anyone?
Posted: Fri Mar 27, 2020 12:09 pm
by Tunneller
Also, Stefan, this is without the nuclear Zeeman, so maybe that doesnt make a difference, at least at this frequency [I will want to drop to 4.3GHz soon though]
I see in the documentation that H_NZI is the spin Hamiltonian term describing the interaction of a nuclear spin with the external magnetic field and has equation [....] which is exactly what I want. But looking at the spin structure Sys I do not see the needed variable name.
I think it might be possible to enter using the Sys.Ham command, so I am looking more into that.
Regards, Johnn
Re: Calcite anyone?
Posted: Mon May 04, 2020 7:13 am
by nwili
Hi Johnn,
it is taken care of automatically when you specify the nucleus in the System structure and the field in the Experiment structure.