Dear President of the Czech Academy of Sciences, Professor EvaZažímalová,
Dear Honorary President of the Czech Academy of Sciences,
Professor Rudolf Zahradník,
Dear colleagues and friends,

Let me to introduce to you Professor Hiroshi Nakatsuji, the laureate of theMedal „De scientia et humanitate optime meritis“Professor Hiroshi Nakatsuji studied in Kyoto and obtained Ph. D. inEngineering (Chemistry) in 1971.
He continued in Kyoto in 1973-1975 he spent 2 years in the US, one
year with Jeremy Musher, and one year with Robert Parr. In 1990 hereceived professorship at the University of Kyoto.
In years 2004 to 2006 he served as director of the famous Fukui
Institute for Fundamental Chemistry, currently he is director of Quantum
Chemistry Research Institute and Professor Emeritus of Kyoto University.
He was visiting professor in Tokyo, Nagoya and Sendai.
Professor Nakatsuji is member of International Academy of Quantum
Molecular Science, where he served as General Secretary in 2012, fellow
of WATOC, and other societies.
He received several prestigious awards, like Fukui Medal from AsiaPacific Association of Theoretical and Computational Chemists, or WATOC
Schrödinger Medal.
He is editor of Journal of Computational Chemistry and serves inseveral Advisory Editorial Boards.
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MAIN RESEARCH ACTIVITIES OF HIROSHI NAKATSUJI
As a quantum scientist, a dream of Hiroshi Nakatsuji has been toconstruct highly predictive and widely applicable theories and concepts thatare useful in the studies of chemistry and physics. He has endeavored tomake his works to be highly original, innovative, simple, intuitive, widelyapplicable, and even beautiful. Further, he has tried to make up his theories
starting from zero up to the useful methodologies in the fields. His main
contributions are summarized as follows.

I. Force Concept of Molecular Geometry Based on the Electrostatic(Hellmann- Feynman) Theorem.
Nakatsuji proposed a conceptual force model, called ESF (electrostaticforce) model for molecular geometries and chemical reactions.

II. Electronic Mechanisms and the Relativistic Effects in NMR
Chemical Shifts.
NMR chemical shifts are very widely used in analytical chemistry but it is
not well known that they involve a lot of information about the electronic
structure of molecules. A purpose of the study of Nakatsuji is to clarify theelectronic mechanisms of the metal chemical shifts and to offer the means
for understanding the natures of bonding in the metal complexes.

III. Dipped Adcluster Model (DAM) for Surface-Molecule Interactions
and Reactions.
Metal surfaces show various important chemical properties, among others,
the catalysis of many important reactions. When you describe surfacemolecule interactions, some modeling is necessary because a surface is an2

infinite system. However, the cluster model that is very often utilized as amodel of a surface is very crude for a metal surface, because it cannotdescribe the effects of the free band electrons that are characteristic of ametal surface.

IV. Wave Mechanics without Wave - Directly Solving the Second-Order
Density Matrix without Using the Wave Function.
When the wave function of a molecule is given, we can calculate theproperties of the molecule by applying the operators on the wave function.
Energy and other electronic properties are such properties. Since any basic
operators of properties include only one- and two-electron operators, all theproperties of molecules can be calculated if the exact second-order density
matrices are given. Therefore, we may construct quantum mechanics using
the second-order density matrix as a basic variable instead of the wave
function (Wave Mechanics without Wave). Nakatsuji presented in 1976 a
basic equation called density equation (or later called "contracted"
Schrödinger equation) which is equivalent to the Schrödinger equation in
the space of the density-matrix. However, it took 20 years before thisdensity equation was solved for real molecules.

V. SAC/SAC-CI Method for Studying Chemistries of Excited andIonized States.
Nakatsuji and Hirao proposed the SAC (symmetry adapted cluster) method
for the ground states of closed and open-shell electronic structures. TheSAC method is a kind of coupled cluster method that takes all the excitation
operators to be symmetry adapted, so that no spin-contamination problem
arises and it leads to a stable convergence to the spin-eigen function. Then,
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Nakatsuji proposed in 1978 the SAC-CI (configuration interaction) method
to describe accurately and efficiently the electronic structures of the excited,
ionized and electron-attached states of molecules (ground and excitedstates of singlet to triplet spin multiplicities).

VI. General Method of Solving the Schrödinger and Dirac-CoulombEquations.
The Schrödinger equation and the relativistic Dirac-Coulomb equation
represent the basic mathematical principles governing chemistry, biology,
physics of matter, and related sciences. So, a central theoretical theme ofthese sciences is to establish a general method of exactly solving these twobasic equations. Thereby, we can do quite accurate predictions of thephenomena without doing experiments, and therefore, this has long been adream of theoretical chemists and physicists, though it was believed
impossible by many scientists including P. Dirac, H. Eyring and others.
Recently Nakatsuji has realized this dream! He found a general method ofanalytically solving the Schrödinger equation, breaking the "dogma"that this equation cannot be solved, which lived for over 80 years since thebirth of quantum mechanics. He solved the singularity problem byintroducing the scaled Schrödinger equation and opened a new fieldrealizing the calculations of accurate analytical solutions of the Schrödinger
equation for general atoms and molecules. His free iterative complement
interaction (ICI) method, compactly called free complement (FC) method,combined with the variation principle gave, for example, the helium groundstate energy correct up to 43 decimal figures. He further established amethod to calculate the accurate analytical solutions of the Schrödinger
equation without doing analytical integrations. This is a very general4methodology that is applicable to any atoms and molecules. Since theSchrödinger equation is the governing principle of chemistry, this meansthat chemistry will gradually change from "empirical" to "logical" science
whose bases are firmly on the principles of quantum mechanics.

5Hiroshi has long-term contacts with Czech science. He is professional
and personal friend of many Czech theoretical chemists, like Professor
Zahradník, or Professor Carsky. In 2003 I was in Boulder and during lunch
break I read his first series of papers on exact solution of Schrödinger
equation. The reading was much more exciting than the American lunch. I
have decided to invite Hiroshi to Prague for our newly established InvitedLecture Series. Hiroshi accepted the invitation and delivered not one, butthree lectures. During the dinner in Villa Lanna Professor Rudolf Zahradníksuggested, that we should not stop contact with a single visit, andsuggested a Japanese-Czech conference. The first one was in Prague in2005. The second was 2 years later in Kyoto, and Hiroshi was the mainorganizer. Currently, the 7th JCS symposium is running in Prague, andHiroshi helped tremendously the organizers with propagation andorganization of the Japanese delegation.

I hope I have convinced you that Professor Nakatsuji is the excellent
laureate of the top Medal of the Czech Academy of Sciences, called „Descientia et humanitate optime meritis“, for excellent services to scienceand humanity.

Thank you for your attention.

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