NQR investigation of intercalation of layered halides with organic compounds

Joumd of Molecular Structure, 83 (1982)353-356 Elsevier ScientificPub~gCompany.Am~am-_PrintedinTheNetherlands

NQR

INVESTIGATION

ORGANIC

INTERCALATION

OF LAYERED

HALIDES

WITH

COMPOUNDS

LYFAR

D.L.

OF

AND

Institute

S.M.

RYABCHENKO

of Physics

Academy

of Sciences

UkSSR,

Kiev,

(USSR)

ABSTRACT The on

NQR

technique

internal

non

fields

interaction We

was

found

used

of the

crystals

in layered

that

to study and

crystals

intercalation

the

influence

the

and

d)

changing of the temperature dependence character cies and spin-lattice relaxation rates. see

that

in the quasi-two-dimensional although tion

temperature

rate

One

The has

(pp).etc.

lattice

other

three

the

data the

theless be

and

the

the due

the heat

in

not

in

decrease

interaction,

and

spin.-lattice

typical

for

capacity.

layer-type

organic

IC

with

1).

The

to

layers

the

relaxa-

three-di-

of the

compound

aniline PbI2

as in PbI2 form

crystals

into

lattice

is their

giving

new

(a) I piperidine

(pp) leads

and when a super parameter

one

to the

ICs PbI2

lattice

with

with

the

in a layer.

for CdI2(a). bonding

("improves" of the

leads in

layered

their

conclusion crystals

dependence

connected

the problem

that

the

and make

three-dimensionality).

of the phonon

of vibrations Hence

to the

temperature

to the modification

contribution

other

(ref.

capacity

interlayer change

of the

IC susbstance

data

on heat

dimensional"

may

of PbIz

or multiple

is no X-ray

creases

are

features

shown

parameter

integral

The

a noticeable

of frequencies

(IC) with

ability

been

compounds,

spacing There

interesting

to intercalate

materials. same

frequen-

crystals.

of the

ability

to

in spin-phonon

compounds

of NQR

of nuclei,

leads

feature

dependence

in intercalated

mensional

positions

intercalation

spin-pho-

of q

ap.oearance

can

of the

CdI2.

c)

One

intercalation

to:

a) changing of the NQR frequencies, appearance of the asymmetry parameter b) of nonequivalent

character

of PbIZ

leads

of

of the heat

IC in-

them

"more

Nevercapacity

spectrum

of the

with

IC substances

the

of investigation

crystal

of the phonon

0022-2860/82/0000-0000/$02.75O1982ElsetierScienticPublishingCompany

to

354

spectrum The

of IC crystals. two-dimensional

in spin-phonon

interaction

been

shown

with

temperature

in

up to T OD manifests In the

(ref.

itself

spin-lattice

The

analysis

crystals

has

for

been

constant

consist

bondings

polarised

been

3-5).

It has

(ref.

crystals

the

linear

The

shown

that

rate

the

(SLRR)

temperature

T1

in

layered

of relaxation

carried

the point is small by

in

change

potentials same

peculiarity

spectra.

in this

of quadrupole

from

spectra

is typical.

crystals

tribution

layered

phonon

-temperature)

relaxation

three-dimensional

investigated

crystals

in intracrystalline

-process

of the

layered

contribution

in NQR

5) it has

of the

were

3) that

of the

(OD is Debay

(ref.

region

nature

out ions

of

crystals in the -3 whilst for

is given by Tl"r -7 . region, Tl+lY

bonding (ref. of the

constants 5) and

for

it was

lattice

in comparison

intrasandwich

dependence

with

electrical

a number

shown

that

in quadrupole that

of the

field

of

of layered the

con-

bonding ion

covalent

layered

crystal.

The NQR technique was used to study the influence of IC on internal fields of the crystals ad the character of the spin-phonon interaction in the layered crystals PbI2 and odI2. It may be expected from X-r= data [ref. I) that in PbI2(pp) all nuclei I'27 (I = 5/2) are equivalent and there are 3 kinds of nonequivslent positions for I 127 in PbI2(a). The temperature (!I?D) dependences of NQR frequency for Pb12(a), PbI2(pp), BI,(a) and for PbI2 and Cd12 two sigfor transitions 3/2-5/2 are shown on Fig- 1. Ke'detected nals for pb12(pp) with the frequencies \r,(5/2+/2) = 20,21 M&z and = 17,l MGz for T -CO, that correspond h-'eq,,Q = 72,8 MGz, V'(3/2-l/2) = -7,21 MGz, h-'eq_& = -65,59 MGz (signs are relative) and h-'eq,Q q = 0,802 f 0,001. 4 signals NQR for PbI2(a) with frequencies at 77 K: = 35,08 MGz, 3,(5/2-3/2) = J1(5/2 --3/2) = 39,85 MGz, 3,(3/2-l/2) 107,78 ?!IGzand V+(3/2-l/2) = 72,25 UGz. For 2 nonequivalent sites Iq27 , therefore, h"eq,,Q = 146,g MGz, h-'eq& = -II,02 PGa, h-'ec Q = -135,88 EGz, 'i! = 0,848 and h-'eqZzQ = 377,46 MGz, h-'es,Q= -86,E%Gz, h-'eq _& = -290,66 MGz, _790 ;d;zO~4d~;:~;;dwe relative). For two sicJnals, their Cd12(a) in frequZ&v region 20 frequencies nt 77 K are $,(5/2-3/2) =165,703 Kz and 32(3/2-l/2) = 67,363 i:XSz., ther~fcze, h~leq,,~ = 556,86 ?IGz, h-' ec,,Q = -2?9,94 XGZ, h",,;& = -7 ,36,92 bsGz (signs sre relative) end q= 0,21. ic

355

Fig.

1.

At

All

the

encies&$

curves

linear

the aniline for TD

with

of NQR

aniline

rigid

shown

relative

into

account

(pp) leads

to more

All

nuclei

part

connected

also

in fig. within

PbI2(pp)

the

the

in soft with

SLRR

Hence, typify

that

though the data two

molecules of Pb12.

the

has

change

its

own

ordinate.

of the NQR

these

data

one may

frequwith

conclude

rigid vibrations responsible 127 which are not connected I

vibrations

like

aniline

contribute

the

2.

TD of SLRR

The

TD

and TD

value

as in the

agree the

TD

indicate

well of

with

the

nuclei

of

to the more

21, the dimensionality of

(pp) provide

more

IC(pp1 in the the

with strict

rigid

conclusion

compounds,

and

and Cd12(a)

More

frequencies

three-dimensional (ref.

IC compounds,

accuracy

changed.

TI

for

for PbI2(a)

the experimental

increasing

compounds

heat quasi

each

vibrations.

coincide with

the

frequency.

We measured are

but

scale,

TD the

Taking

(I21 take

The nuclei

Pb12.

same

of the

molecule.

IC PbI2

with

part

the

for PbI2(pp) and for the signal NQR of /b&,decreases 127 (II) conntected, we assume, attributed to the nuclei I

PbI2(a) that

have

TD

SLRR TD

for

phonon

from and

the

their

SLUR

the

practically

for Pb12, PbI2(pp)

spectrum

but

for

together of IC

TD of frequencies.

in Pb12(pp)

as distinct

results

from

the

do not specific

lead to a noticeable decrease of spin-phonon interaction. So the additional connection between the layers

356

Fig. 2. The temperature At the

the

NQR

same

time,

of nuclei

PbI2(a)

compared

gradient

value

ably

compared

dependencies

all

I not

of the

the features of quasi two-dimensionality directly connected with aniline molecules

to 2HPbI2 of the

with

SLEW.

remain practically intracrystalline field

in in

the same, though the itself changes consider-

2H Pb12.

Y,V.Kukol, P.P.Milner, Yu.R.Zabrodsky, Yu.N.Dmitriev, F.I.Brintcev, Fia. T%. Tela, 19 (1977)1608-1612. k.M.Gurevich, A.V.Akpina, Yu.k.Dushe.2 B.I.Verkin, B.Y.Suhsrevskig, &kin, Fiz. Niak. Temp, 2(1976)946-948. V.E.Goncharuk, D.L.Lyfar., S.M.mabchenko, Fiz. TV. 3 M.D.Glinchuk, Tela, 18(1476)15-22. 4 D.L.Lyfar', V.E.Goncharuk, S.bLHyabchenko, Phys. St. al.@), I

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Teor.

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