Electronic States of Inorganic Compounds: New Experimental Techniques: Lectures Presented at the NATO Advanced Study Institute held at the Inorganic Chemistry Laboratory and St. John’s College, Oxford, 8–18 September 1974

541 Pages·1975·15.98 MB·English

by  C. J. Ballhausen (auth.), P. Day (eds.)

Electronic States of Inorganic Compounds:
New Experimental Techniques
NATO ADVANCED STUDY INSTITUTES SERIES
Proceedings of the Advanced Study Institute Programme, which aims
at the dissemination of advanced knowledge and
the formation of contacts among scientists from different countries
The series is published by an international board of publishers in conjunction
with NATO Scientific Affairs Division
A Life Sciences Plenum Publishing Corporation
B Physics London and New York
C Mathematical and D, Reidel Publishing Company
Physical Sciences Dordrecht and Boston
D Behavioral and Sijthoff International Publishing Company
Social Sciences Leiden
E Applied Sciences Noordhoff International Publishing
Leiden
Series C - Mathematical and Physical Sciences
Volume 20 - Electronic States of Inorganic Compounds:
New Experimental Techniques
Electronic States of
Inorganic Compounds:
New Experimental Techniques
Lectures Presented at the NATO Advanced Study Institute
held at the Inorganic Chemistry Laboratory and St. John's College,
Oxford, 8-18 September 1974
edited by
P.DAY
St. John's College, Oxford, England
D. Reidel Publishing Company
Dordrecht-Holland / Boston-U.S.A.
Published in cooperation with NATO Scientific Affairs Division
Library of Congress Cataloging in Publication Data
NATO Advanced Study Institute, Oxford, 1974.
Electronic states of inorganic compounds.
(NATO advanced study institutes series: C, mathematical and physical sciences; 20)
Bibliography: p.
I. Chemistry, Inorganic-Congresses. 2. Excited state chemistry-Congresses.
I. Day, Peter R., 1928- II. North Atlantic Treaty Organization. Division of Scientific Affairs.
III. Title. IV. Series: NATO advanced study institutes series: Series C, mathematical and physical
sciences ; 20.
QD475.N37 1974 547'.1 '3 75-17752
ISBN-13: 978-94-010-1862-3 e-ISBN-13: 978-94-010-1860-9
DOl: 10.1007/978-94-010-1860-9
Published by D. Reidel Publishing Company
P.O. Box 17, Dordrecht, Holland
Sold and distributed in the U.S.A., Canada, and Mexico
by D. Reidel Publishing Company, Inc.
306 Dartmouth Street, Boston, Mass. 02116, U.S.A.
All Rights Reserved
Copyright © 1975 by D. Reidel Publishing Company, Dordrecht, Holland
Softcover reprint of the hardcover 1st edition 1975
No part of the material protected by this copyright notice may be reproduced or utilized
in any form or by any means, electronic or mechanical, including photocopying,
recording or by any informational storage and retrieval system,
without permission from the copyright owner
CONTENTS
PREFACE VII
C. J. Ballhausen
BASIC THEORY OF THE ELECTRONIC STATES OF MOLECULES
J. M. Thomas
A CHEMISTS' GUIDE TO THE BAND THEORY OF SOLIDS 27
J. Ferguson
INTRODUCTION TO THE LINEARLY POLARIZED ELECTRONIC SPECTRA
OF INORGANIC CRYSTALS 59
P. J. Stephens
VIBRATIONAL-ELECTRONIC INTERACTIONS 95
D. S. McClure
INTERCONFIGURATIONAL AND CHARGE TRANSFER TRANSITIONS 113
P. J. Stephens
THEORY OF MAGNETIC CIRCULAR DICHROISM SPECTROSCOPY 141
R. G. Denning
THE TECHNIQUE OF MAGNETIC CIRCULAR DICHROISM 157
B. Briat
APPLICATIONS OF MAGNETIC CIRCULAR DICHROISM TO CHARGE
TRANSFER AND LIGAND FIELD SPECTRA 177
P. N. Schatz 4+
MCD SPECTRA OF CHARGE TRANSFER TRANSITIONS: OCTAHEDRAL Ir 223
A. J. Thomson
MAGNETIC CIRCULAR DICHROISM SPECTROSCOPY OF MATRIX ISOLATED
SPECIES 241
A. J. McCaffery
CIRCULARLY POLARISED EMISSION SPECTROSCOPY 255
VI CONTENTS
A. F. Orchard
PHOTOELECTRON SPECTROSCOPY AND ALLIED TECHNIQUES:
GENERAL INTRODUCTION 267
D. R. Lloyd
ULTRAVIOLET PHOTOELECTRON SPECTROSCOPY OF MOLECULES IN THE
GAS PHASE 305
A. F. Orchard
ULTRAVIOLET PHOTOELECTRON SPECTROSCOPY OF TRANSITION METAL
COMPOUNDS 339
C. R. Brundle
VALENCE LEVEL PHOTOELECTRON SPECTRA (XPS AND UPS) OF SOLIDS
AND INTERFACES 361
G. K. Wertheim
MULTIPLET SPLITTING IN THE X-RAY PHOTOEMISSION SPECTRA OF
OPEN-SHELL IONS 393
C. E. Johnson
X-RAY PHOTOEMISSION FROM CORE ELECTRONS IN SOLIDS 409
C. R. Brundle and A. D. Baker,
TECHNIQUES RELATED TO PHOTOELECTRON SPECTROSCOPY 425
D. S. Urch
X-RAY SPECTROSCOPY 449
M. T. Hutchings
THE USE OF INELASTIC NEUTRON SCATTERING TO DETERMINE THE
ELECTRONIC STATES OF INORGANIC MATERIALS 495
PREFACE
In the last few years a surprisingly large number of new
experimental techniques have been devised to probe, often with
great subtlety, into the electronic structures of inorganic
substances. Thus in favourable cases one now has the opportunity
of locating and assigning electronically excited states over a
vast energy range stretching from tens of cm-1 above the ground
state up to some 106 cm-1• The techniques are extremely dis
parate in background, involving (among others) linearly and
circularly polarised electromagnetic radiation, electron kinetic
energy analysis and neutron scattering. Furthermore, practition
ers of many of the techniques may not be aware of how the
information which they are obtaining overlaps and complements
that obtained by other techniques. The time therefore seemed
ripe to bring together a group of experts to survey, for an
audience of inorganic chemists, the basic theories and experim
ental procedures relevant to the different techniques, and the
relations between them. In pursuing this aim we were fortunate
in having the very generous financial backing of N.A.T.O.,
through their Advanced Study Institutes programme, and the
present volume records the substance of lectures given at the
Institute which took place at the Inorganic Chemistry Laboratory
and St. John's College, Oxford, from 8-18 September 1974.
However, the volume is much more than a set of 'Proceedings';
by its completeness it comprises, rather, a textbook of the
new methods which should prove a useful guide for all inorganic
chemists interested in the electronic structures, both of
molecules and continuous lattice solids.
As the Director of the Institute I am deeply conscious of,
and extremely grateful for, the efforts of the other members of
the Organizing Committee, Mr. A.F. Orchard, Professor C. Furlani
and Professor L. Oleari, for the care taken by the lecturers in
preparing their material for publication, and finally to my wife
for typing the entire manuscript. Everyone concerned in the
Institute will also be grateful to the staff of the Inorganic
VIII PREF ACE
Chemistry Laboratory, to the equipment manufacturers for their
illuminating demonstrations, to the President and Fellows of
st. John's College for their permission to use the College
premises and to the N.A.T.O. Scientific Affairs Division for
their financial assistance.
P. DAY
Oxford, March 1975
BASIC THEORY OF THE ELECTRONIC STATES OF MOLECULES
C.J. Ballhausen
Chemical Laboratory IV, H.C. ¢rsted Institute,
Universitetsparken 5, Copenhagen ¢, Denmark
ELECTRONIC AND NUCLEAR COORDINATES
The wave-functions for a molecule are dependent both on the
nuclear and electronic coordinates. The first task is, therefore,
to try to separate the electronic and nuclear motions. We
designate the coordinates and masses of the nucleus ~ (Qp' M~)
and the coordinates and masses for the electrons (ri,m), where
all coordinates! and ~ 'are referred to a laboratory fixed co
ordinate system. The total non-relativistic Hamiltonian for a
molecular system of ! nuclei and electrons is
~
,,~ 2 "'\ t-1 2
- L 2M V~ - 4- 2m V i + V(r,Q)
",,]I- ...
V(r,Q) is the potential 'energy term equal to
Z e2 I Z Z e2 +I e 2
IJI'
V(r,Q) - IQ -r.,+ IQ" ,-\QI I I r i -r j \ (2)
/AI. 'I" 1 ,,"V JI' II i<j
Let us now suppose that all the nuclear masses are infinite.
Clearly, this will quench the nuclear motions, leading to an
'electronic' Hamiltonian of the form
~ {.,2 2
- L -2 V· + V(r,Q)
. m 1
1
P. Day (ed.), Electronic States of Inorganic Compounds. 1-25. All Rights Reserved.
Copyright © 1975 by D. Reidel Publishing Company, Dordrecht-Holland.
2 C. J. BALLHAUSEN
The 'electronic' Schrodinger equation is then defined as
Both W (Q) and± (r,Q) are seen to contain the nuclear coordinates
Q as p~rameters,nand are indeed continuous functions of the 3N
nuclear coordinates. In principle, we could solve (4) for all
values of the 3N nuclear coordinates, and for each nuclear
arrangement we will obtain a complete set of electronic wave
functions ±n(r,Q) and eigenvalues Wn(Q). In order to treat the
motions of the nuclei we introduce the so-called normal co
ordinates. This involves changing from the external coordinates
Q to an internal molecular coordinate system 5.
Let us assume that we can find at least one point, QO, in
the 3N dimensional coordinate system for which all the first
derivatives of Wn(Q), with respect to Q, are equal to zero. Thus
(5)
Obviously the function Wn(Q) will have an extremum at the point
QO. Whether QO represents a minimum or a maximum depends, of
course, upon the values of the second derivatives of W (Q).
n
In the case where (5) cannot be fulfilled, and at least one
of the 3N derivatives is different from zero for all values of
the nuclear coordinate, this simply means that the potential
hypersurface cannot have a minimum with respect to this nuclear
coordinate, and that the corresponding molecular state is unstable.
However, if for some point QO equation (5) can indeed be fulfilled,
QO will be taken to represent a stable configuration of the
molecule in the s~ate 'f (r, Q).
n
We no., introduce a set of 3N mass-weighted displacement co-
ordinates S1 •••••. S3N defined as
S 1 =.Jii1 ( Q1x - Q~ x)
S2 = ~ (Q1y - Q~y)
S3 = ,[M1: Q1z - Q~ z) ( 6 )