CONCLUDING REMARKS

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CONCLUDING REMARKS

R. Haensel

To cite this version:

JOURNAL DE PHYSIQUE Colloque C4, su/)/~lPn~ent au no 7, Tome 39, Juillet 1978, page C4-233

CONCLUDING

REMARKS

R.

Institut fiir Experimentalphysik. Universitat Kiel. Kiel, Germany

When in 1962 Pr. Weissler organized the first meeting of this series in Los Angeles, it was certainly not intended as a permanent institution. It was just the desire, to bring together the quite limited number of people, who worked on Vacuum Ultraviolet Radia- tion Physics problems in a number of fields, e.g. atomic, molecular and solid state physics, astrophy- sics etc. Very little theory was done at that time ;

it was more a general technical interest, which brought the different people together and certainly also the desire to exchange their results.

It was then a specific interest of solid state physi- cists to hold a second meeting of its kind. This meeting was organized 1968 by Dr. Arakawa in Gatlinburgl Tennessee. At this meeting the emphasis was on a comparison of optical spectroscopy and electron energy loss measurements for the determination of optical constants of solids.

In the next conference 1971 in Tokyo atomic and molecular physics were resumed, since the mutual correlations between atomic and solid state spectro- scopy became quite obvious. From then on, the gene- ral frame of the conference remained the same, including the interval of three years between the conferences leading to Hamburg 1974 and Mont- pellier 1977. Consequently the next conference will be organized in 1980 by Dr. R. P. Madden of the National Bureau of Standards, Washington1D.C.

When the program of the Montpellier conference came out, it looked very similar to that of the Hamburg meeting. During the conference, however, it became very clear, that in some specific areas considerable progress was achieved. The field of photoelectron spectroscopy, introduced to the conference series in Gatlinburg by Pr. Spicer and a small number of contributed papers (one of them dealing w;th the influence of adsorbed gases to the photoelectron yield) grew up to a highlight at the Montpellier conference. Angular resolved photoemission, constant initial and constant final state photoemission spectro- scopy brought very interesting results on the electronic structure of solids.

The mutual interaction between atomic and energy band picture for the description of the optical spectra of solids became clearer and clearer. Many body effects and correlation phenomena developed for

atoms or solids respectively proved to be applicable to the other field.

The fraction of contributions from synchrotron radiation laboratories increased again, but the orga- nizers were not overcome by the temptation to convert the Vacuum Ultraviolet Radiation Physics Confe- rence into a Synchrotron Radiation Conference.

A field which played a relatively small role in

Montpellier, but will increase in the next three years, is time resolved spectroscopy for the investigation of dynamical processes in the radiative and non radiative energy dissipation of excited solids and molecules. More attention will also be paid to the simultaneous optical and structural investigation of the same sample, where up to now both aspects were mostly studied on different samples. EXAFS-, LEED- and X-ray diffraction devices (including energy dis- persive systems) will be therefore more and more incorporated in sample chambers for optical measu- rements.

These trends have been made possible by corres- ponding developments and improvements of advanced instrumentation : synchrotron radiation in the past was mostly available only by parasitic use of synchro- trons and storage rings built for elementary particle physics, but in a few years several storage rings will be working, which were exclusively constructed to serve as radiation sources. An interesting aspect in this connection will be the development of vacuum ultraviolet lasers and the wavelength at which synchro- tron radiation and lasers become competitive. Impor- tant technical contributions to ultraviolet spectro- scopy also came from progress in ultrahigh vacuum technology and the development of fast electron sources and detectors. Of special interest is the deve- lopment of holographic gratings. In Hamburg 1974 first examples of holographic plane and spherical gratings were available only through special relations to the manufactures but now even toroidal grating can be selected from the catalogue. Interesting will also be future progress of transmission gratings and zone plates for the soft X-ray regime. So generally the future of the next conferences seems to be clear, at least as far as fundamental research is concerned. It will be, however, of great importance for our field to show to what extent it can be useful for other

C4-234 R. HAENSEL

disciplines in science and technology. This question is also raised by the fact, that our instrumentation has become rather expensive. In this respect X-ray microscopy, X-ray lithography, surface analysis with possible applications to catalysts chemistry, plasma diagnostics and aeronomy will be of increasing importance.

In summarizing we can say, that the Montpellier conference was very successful in that it brought many answers to questions, which kept us busy for many years, and showed very clearly trends for future developments. The credit for this success goes first of all to the invited speakers, which were all of high quality and then to the increasing number of contri- butors. The latter caused some problems to the organizers, which were not convincingly solved by overburdened poster sessions. Here a restriction of topics or the rigorous rejection of papers may be the

only solution for the future. Therefore, it is a big pleasure to thank the large number of people, who helped to make this conference so successful. First of all we have to thank the University of Montpellier for the hospitality and especially Madame Pr. S. B. Robin-Kandare and her collaborators (namely Dr. and Madame Ferraton) for all their help. All above, however, we have to thank the organizing and the program committees with Pr. Vodar, Dr. Farge and Dr. and Madame Pouey and all the other members, who all devoted a good fraction of their time in the last years for the preparation of the conference.

We had a great conference both as the scientific and the social aspects are concerned. The medieval banquet in the Palais des Papes in Avignon deserves special recognition. It will cause some extra problems to the organizers of the next conference.