Download University of Groningen Point defects in apatites Knottnerus, Daniel

University of Groningen
Point defects in apatites
Knottnerus, Daniel Ivo Meinhard
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Publication date:
1976
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Citation for published version (APA):
Knottnerus, D. I. M. (1976). Point defects in apatites s.n.
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Sunnary
Thls thesls
sorptlon
investigations
in synthetic
A short
ls a report
of some rnagnetlc resonance and optlcal
concernlng
is given in (hapter
mental aspects
of crystal
I.
magnetic experiments
is developed.
ters
are reported
ted with
optical
resonance are highly
the oxygen impurities,
as well
as
spectros-
and optical
the explanation
of CIAP eontaining
crystals
It
turns
absorption
out that
all
techniques
anisotropic
which are built
of the
cen-
or elec-
and can be associa-
in
substitutionally
at
sites.
the chiorine
A comparison with similar e:<periments on fluorapa)(CarO(PO4)6Fo) doped with o- yields the models for the electron-
excess centers
to
The properties
X-irradiation
ved. This line
tigated
in Chapters V to VII.
one single,
is
is
nearly
of the orientation
this
detail
centers.
Chapter V deals with
line
At
is obser-
resonance line
centers
as indicated
by the
cannot be observed any longer
is disconnected
of the crystal
from the
centers
additional
presumably
are
to
(OCl)2-
the EPR spectra
(ocl)2-
4
observed
centers
also;
molecular
centers
molecular
are
The centers
ob-
belonged originalty.
magnetic
observed.
ions,
arê inves-
ions where the 02- ion
to which it
moreover,
ori-
as a function
in the magnetic field.
(PO,)3- group,
hole-excess
also
These hole-excess
by determining
served at 77 K are attributed
centers,
after
crystals
obseured by an overwhelming arnount of resonance lines
in greater
nes due to
isotropic
due to electron-excess
from hole-excess
5 K these
centers
at 4 K, 77 K, and 300 K in pure crystals.
At lower temperatures
because it
ginating
of pure and sodium doped CIAP single
obtained
room temperature
hole-excess
(OCl)2- molecular ions.
are described
the EPR results
g-value.
The paramagnetic
observed optically.
can be attributed
At
single
1n Chapter ïV.
observed at 300 K by either
tron paramagnetic
tite
necessary for
of X-Írradiated
crystals.
is devoted to the experi-
growth and of magnetic
the theory,
inpurities,
group, mineral
Chapter II
copy. In Chapter III
The properties
of X-ray lnduced defects
(CIAP, CalO(PO4)6C12) single
calcir:mchlorapatite
survey of the members of the apatite
synthetic,
O-
the nature
ab-
For
resonance
these
no more detailed
li-
latter
models
can b
is
constructed
with
isotropic
approximately
axes of the g-tensor
lon dÍrectlon
any certainty,
and, furtherrcre,
do noÈ coincide
ín the crystal
doped ClÀP is
growth,
have lost
cal
crystals
CIAP. The optical
absorption
kinds of crystals
for all
temperature
tical
after
between the main optical
The resolved,
center,
the single
Chapter VIII
the fluorlne
of defects
gives
rise
2
trapped
exist
to a doublet
X-ray diffraction
at
(55 to 77 K)
are created
in un-
magnetic resonance
a more resolved
and optical
bleaching.
in Chapter VII
pattern
is attrlbuted
spectrwr
The combined opa corre.-
resonance
spec-
to a perturbed
F-
on the position
indicates
that
two different
The OH-F-vacancy configuration
H-F distances
of
(CarO(PO4)6(OH)2. The obser-
and the symmetric OH-F-HO configuration
data for mineral
is
F-center.
hydroxylapatite
in these minerals.
pattern
do not reveal
about an NMR investigation
The calculated
the same
at CaCl, vacancies
bands and these magnetic
absorption
than in undoped
temperatures
from the single
to an unperturbed
reports
fluorine
t)pes
with
line
ions in mineral
ved five-lÍnes
in a triplet.
seven-lines
CIAP:Na+
trapped at CaCl, vacancies.
apart
thermal
in
The observed'primary'bands
At higher
one or two electrons
addiÈional
for
at 5 K are nearly
to electrons
and EPR e:<periments described
lation
tra.
are also obtained
obser:ved at 300 K ln undoped crystals,
obtained
77 K, opti-
from the ones reported
and more eomplex centers
ïn sodium doped crystals,
crystal
but in pure crystals
than approximabeLy
obtained
(F-centers).
spectra
a few months after
ls much higher
investigated.
become r:nstable
doped crystals:
llne
spectra
spectra
are attributed
and at anion-vacancles
these centers
higher
dlfferent
SLmilar
in pure
centers
The absorption
crystals,
which the colorabillty
for
ion-
unperturbed
about six months these pure crystals
After
completely
Chapter IV are observed.
single
O2'doped
CaCl, and, at temperatures
speëtra
VI.
observed within
is much lower.
absorption
this
Ín (hapter
reported
are the same as those of
the colorablllty
any particular
wlth
observed electron-excess
pure cl-ystals,
in X-Írradlated
of the main
the directions
lattLce.
Thê study of the optlcally
and sod|:n
interactlon
because the hyperfine
are in excellent
fluor-
results
agreement
and hydroxylapatite,