Introduction
Metal clusters possess intriguing properties such as an increased magnetic moment or enhanced, size-selective fluorescence that promise versatile applications. This implies, however, nanostructured bulk systems providing sufficient thermal, mechanical, and chemical stability. We have set up a new experiment that allows the preparation of well-defined metal clusters in matrices stable at ambient conditions, i.e. room temperature and atmospheric pressure. Our setup allows us to independently vary cluster and matrix material, concentration and cluster size between atom and many thousands of atoms. Samples of both miscible as well as immiscible materials can be produced in meta-stable configurations that are not accessible by e.g. thermal aggregation. These nanostructured samples can then be used as well-defined, tailor-made benchmark systems for various physical properties.
Experiment
The experimental setup used to generate cluster-assembled materials is shown in fig. 1, a detailed description can be found in [1]. The home-built magnetron cluster ion source following the design of Haberland et al. [2] is followed by several differential pumping stages through which the clusters are transferred with an octopole ion guide. A static quadrupole deflects the ion beam either towards a time-of-flight mass spectrometer, where the beam is characterized and optimized, or towards the deposition chamber. Between the deflector and the substrate, a quadrupole mass spectrometer allows filtering single masses and preparing mass-selected samples. The matrix is evaporated in a commercial 270° electron beam evaporator and co-deposited with the cluster beam. Experiments on the physical properties are performed ex-situ. Absorption and fluorescence studies use either deuterium or tungsten lamps or an OPO laser system together with a CCD equipped spectrometer. Magnetic as well as transport measurements are performed in collaboration with the group of Prof. J.-Ph. Ansermet in our institute.
Bruce Merrifield was born in Fort Worth, Texas, July 15, 1921, the only son of George E. and Lorene (Lucas) Merrifield. In the spring of 1923 they drove across the southwest desert to settle in California where they lived in several cities throughout the state.
He attended nine grade schools and two high schools before graduating from Montebello High School in 1939. His interest in chemistry began there and he also enjoyed the astronomy club where he ground a mirror and built a small reflecting telescope. As a senior he managed to be runner up in the annual science contest and in the process learned a valuable lesson in the scientific method.
College began at Pasadena Junior College and at the end of two years he transferred to the University of California at Los Angeles (UCLA). After graduation in chemistry he worked for a year at the Philip R. Park Research Foundation taking care of an animal colony and assisting with growth experiments on synthetic amino acid diets. One of these was the experiment by Geiger that first demonstrated that the essential amino acids must be present simultaneously for growth to occur.
It soon became clear that more education was necessary and he returned to graduate school at the UCLA chemistry department with professor of biochemistry M.S. Dunn to develop microbiological methods for the quantitation of the pyrimidines. Graduation was on dune 19, 1949, on June 20 he and Elizabeth Furlong were married, and on June 21 they left California for New York City and the Rockefeller Institute for Medical Research.
At the Institute, later Rockefeller University, he worked as an Assistant for Dr. D.W. Woolley who was to have a profound influence on his career. They worked on a dinucleotide growth factor he discovered in graduate school and on peptide growth factors that Woolley had discovered earlier. These studies led to the need for peptide synthesis and, eventually, to the idea for solid phase peptide synthesis in 1959. The development and application of the technique have occupied him and his laboratory up to the present date. He is very proud of the fact that his office was once occupied by the great pioneer peptide chemist, Max Bergmann, and has been inspired by the knowledge that his laboratories were once filled with names like Leonidas Zervas, Joseph Fruton, Klaus Hoffmann, Emil Smith, William Stein, and Stanford Moore.
In the meantime his wife, Libby, who was a biologist by training, stayed home in Cresskill, New Jersey, and raised their six children who now range in age from 19 to 32 years. They have been the great joy in the life of their parents; and now Jim has a daughter, Kelly, who is the pride of the whole family. Three years ago Libby joined the Merrifield laboratory at Rockefeller University.
He was a Nobel Guest Professor at Uppsala University in 1968 and was elected a member of the U.S. National Academy of Sciences in 1972. He has received several awards for his work on peptide chemistry including the Lasker Award for Basic Medical Research (1969), the Gairdner Award (1970), the Intra-Science Award (1970), the American Chemical Society Award for Creative Work in Synthetic Organic Chemistry (1972), the Nichols Medal (1973), the Instrument Specialties Company Award of the University of Nebraska (1977), and the 2nd Alan E. Pierce Award of the American Peptide Symposium (1979).
He has received honorary degrees from the University of Colorado (1969), Uppsala University (1970), Yale University (1971), Newark College of Engineering (1972), the Medical College of Ohio (1972), Colgate University (1977), and Boston College (1984). In 1984 he was appointed the John D. Rockefeller Jr. Professor of the Rockefeller University.
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