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and In the IAU Symposium of 1979 devoted to interstellar molecules
[8]. Excellent relevant monographs [ 9. 10] . related timely
proceedings [ 11] . and recently published elementary textbooks
[12. 13] further help to define the pedagogical scope of molecular
astrophysics. A significant financial investment has been made in
the establishment of ground- and satellite-based observationai
facilities for molecuiar astrophysical studies. In the coming
years. a wealth of experimental data is bound to accumulate. in
which connection close interactions between observers.
astrophysical modeliers. and molecular physicists and chemists can
play a helpful role in analysis and interpretation. In view of the
increasing pace of activity in the field of molecular astrophysics.
and in the apparent absence of relevant international meetings
since the Liege 1977 and IAU 1979 Symposia. it was deemed
appropriate and timely by the organizers to hold a workshop in
1984. Consequently. the NATO Advanced Research Workshop. "Molecular
Astrophysics State of the Art and Future Directions". was organized
and held at Bad Wlndshelm. West Germany. from 8 to 14 July 1984.
The choice of speakers and subject matter of the Workshop was
largely subjective. but designed to include most of the generally
accepted areas of molecular astrophysical study. Workers from the
fields of radio. infrared. and uv-optlcal observations.
astrophysical modelling. laboratory spectroscopy. reaction
chemistry. collision physics. and theoretical molecular physics and
chemistry. were Invited to present survey lectures In their areas
of speciality. In addition.
Comet nuclei are the most primitive bodies in the solar system.
They have been created far away from the early Sun and their
material properties have been altered the least since their
formation. Thus, the composition and structure of comet nuclei
provide the best information about the chemical and thermodynamic
conditions in the nebula from which our solar system formed. In
this volume, cometary experts review a broad spectrum of ideas and
conclusions based on in situ measurement of Comet Halley and remote
sensing observations of the recent bright Comets Hale-Bopp and
Hyakutake. The chemical character of comet nuclei suggests many
close similarities with the composition of interstellar clouds. It
also suggests material mixing from the inner solar nebula and
challenges the importance of the accretion shock in the outer
nebula. The book is intended to serve as a guide for researchers
and graduate students working in the field of planetology and solar
system exploration. Several special indexes focus the reader's
attention to detailed results and discussions. It concludes with
recommendations for laboratory investigations and for advanced
modeling of comets, the solar nebula, and the collapse of
interstellar clouds.
A quantitative measure of the accuracy of the rate coefficients and
the excess energies is a desirable goal of this analysis. There are
two major sources of uncertainties: The atomic and molecular data
and the solar irradiance. The cross sections and branching ratios
used in this analysis come from many different sources; many of
them without any error indications. For this reason, we must
confine ourselves to a qualitative indication of the reliability of
the results. Specifically we give a quality scale in Table II for
the data of each mother molecule; A indicating the highest quality
of atomic and molecular data and F the lowest quality. The letter B
typically means that the threshold is uncertain. For most molecules
the cross section at threshold is very small and the rate
coefficient for these molecules is therefore not influenced by this
uncertainty. For atomic species the cross section is usually large
near threshold, but for these species the threshold is known quite
accurately. The letter B, therefore, indicates that the rate
coefficient is most likely quite accurate, but the excess energy is
less accurately known. The letter C usually means that the
branching ratios are not well known. This means that the total rate
coefficient is very good, but the rate coefficients and the excess
energies for the individual branches are less accurate.
Comet nuclei are the most primitive bodies in the solar system.
They have been created far away from the early Sun and their
material properties have been altered the least since their
formation. Thus, the composition and structure of comet nuclei
provide the best information about the chemical and thermodynamic
conditions in the nebula from which our solar system formed. In
this volume, cometary experts review a broad spectrum of ideas and
conclusions based on in situ measurement of Comet Halley and remote
sensing observations of the recent bright Comets Hale-Bopp and
Hyakutake. The chemical character of comet nuclei suggests many
close similarities with the composition of interstellar clouds. It
also suggests material mixing from the inner solar nebula and
challenges the importance of the accretion shock in the outer
nebula. The book is intended to serve as a guide for researchers
and graduate students working in the field of planetology and solar
system exploration. Several special indexes focus the reader's
attention to detailed results and discussions. It concludes with
recommendations for laboratory investigations and for advanced
modeling of comets, the solar nebula, and the collapse of
interstellar clouds.
A quantitative measure of the accuracy of the rate coefficients and
the excess energies is a desirable goal of this analysis. There are
two major sources of uncertainties: The atomic and molecular data
and the solar irradiance. The cross sections and branching ratios
used in this analysis come from many different sources; many of
them without any error indications. For this reason, we must
confine ourselves to a qualitative indication of the reliability of
the results. Specifically we give a quality scale in Table II for
the data of each mother molecule; A indicating the highest quality
of atomic and molecular data and F the lowest quality. The letter B
typically means that the threshold is uncertain. For most molecules
the cross section at threshold is very small and the rate
coefficient for these molecules is therefore not influenced by this
uncertainty. For atomic species the cross section is usually large
near threshold, but for these species the threshold is known quite
accurately. The letter B, therefore, indicates that the rate
coefficient is most likely quite accurate, but the excess energy is
less accurately known. The letter C usually means that the
branching ratios are not well known. This means that the total rate
coefficient is very good, but the rate coefficients and the excess
energies for the individual branches are less accurate.
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