WORKSHOP
The
role of laboratory experiments
in
the characterisation of cosmic material
Bern,
8 – 12 May 2000
Reports
of the Working Groups
Composition
of the Working Groups
|
Carbon-based
materials
|
|
Participants: G. Baratta, P.
Brechignac, O. Guillois, C. Joblin, V. Mennella, H. Mutschke, C. Reynaud, F. Salama, S. Wada |
Silicon-based
materials
|
|
Participants: J.R. Brucato, L. Colangeli, Th. Henning, F. Huisken, C.
Jaeger, E.K. Jessberger, A. Jones, F. Molster, V. Pirronello, L.B.F.M.
Waters |
Ices
|
|
Participants: M. Bernstein, P. Ehrenfreund, A. Kouchi, M.H.
Moore, M.E. Palumbo, St. Schlemmer, W. Schutte, G. Strazzulla, A.G.G.M. Tielens, N. Watanabe |
Report
of working group on "Carbon-based materials"
We first discussed the production
techniques of carbon materials in the laboratory in a purely technical
point of view. In a second report, we will discuss the application of
laboratory experiments to specific astrophysical issues.
We agreed that the main
parameters that need to be controlled to perform laboratory experiments that
are relevant for astrophysical applications are:
Size – Structure – Chemical
composition – Morphology – Degree of isolation – Temperature of the samples.
The production of materials
is a trade off between accuracy and flexibility.
For example in the cases
where the degree of isolation is poor (grains), the flexibility in the handling
of the sample allows an easier investigation. Inversely, when better
reproduction of the interstellar conditions is obtained (as in matrices,
supersonic jets, beams and/or and traps), higher-sensitivity detection
techniques are needed.
We reviewed the production
techniques:
· Condensation from
the gas phase (hydrocarbon flames and plasmas, laser pyrolysis, graphite
evaporation, ablation or sputtering in various atmospheres, arc discharge,
chemical vapor deposition)
· Pyrolysis of
organic molecules
· Catalytic
processes
· Electron and ion
bombardment
· Photolysis of
ices and organic compounds
The characterization of the
materials is made primarily through the measurement of their optical properties
allowing an assessment of their relevance to astrophysical applications as well
as a follow up of the modifications induced in their characteristics with the variation
of the production parameters.
The recommended approach is
to
1. Simulate (as
closely as possible) the cosmic conditions in the production process and in the
spectroscopy (constrain the number of parameters)
2. Use all available
techniques to form well-characterized products.
3. Compare to
astronomical spectra.
Note: In laboratory
astrophysics studies, the objective is to create a specific environment.
We discussed the increasing
degree of isolation obtained when going from solid inert gas matrices (MIS) to
jets, beams and ion traps.
These techniques provide
controlled environments, a way to trap reactive species and a tool to measure
the intrinsic spectral signatures of the samples. By adjusting/controlling the
various parameters, one can control the size, the chemical composition, the
degree of crystallinity, the photostability and the charge state of the
samples.
We then discussed the processing
of the materials, identifying the following mechanisms:
1. Photophysical
processing
2. Thermal
processing
3. Chemical
processing (reaction with H, H2, C, C+)
4. Ion bombardment
5. Grain-Grain
collisions
6. Grain-Gas
collisions
In all cases, we stressed
the need for quantitative measurements for a correct comparison/ extrapolation
to astrophysical problems (see Tables I and II for the degree of relevance of
various laboratory techniques in this domain).
We noted that, for cases 1
and 4 in particular, the IS values of flux and fluences are often uncertain
although they are critical in the laboratory studies of solid samples (grains).
In the case of molecules, where single photon processes are dominating, the
knowledge of the photon energy is required.
In the cases of grain-grain
collisions (5), where low and high-energy regimes must be distinguished, much
laboratory work is needed for coagulation and shattering mechanisms.
Similarly in the case of
grain-gas collisions, much laboratory work is needed for sticking mechanisms.
We also stressed out the
largely unexplored domain of shocks in the laboratory (with the exception of
some studies of shock initiated graphite –to– diamond transition by either
detonation, projectile-induced or laser-induced shock waves).
We concluded our discussion
by a comparative assessment of the characterization methods in
the laboratory. All the techniques listed below are needed. We reached a
general consensus that the interest of a given method is mainly related to its
ability to produce the data necessary to recover the optical spectra that
should be produced under the relevant astrophysical conditions.
· FUV – FIR
spectroscopy and Photoluminescence is, obviously, the most important tool for
direct comparison with astronomical data. Wide wavelength coverage is needed.
Important progress has been made recently in this domain as illustrated in Figures
1 – 3 (jets, beams, R2PI, CRDS,…).
Quantitative Absorption (UV – Visible) and Emission (IR) studies are required
(wavelength determination for molecular species, indices for solids).
We also noted the lack of information (in astronomical and laboratory data) in
the submm range as well as a need for the study of structure (shape) effects in
the FIR.
· Mass spectrometry
and Chromatography are important in 3 aspects: analysis, size selection and
reactivity studies (Figure 4).
· TEM, SEM, AFM:
important microscopy techniques for structure and size characterization of
grains, need for high resolution and quantitative analysis.
· Raman, EELS, PES,
XPS, XAS spectroscopy: determination of vibrational/electronic properties and
indirect determination of composition and structures.
Cosmic carbon abundance is
constrained. The recent revision of the cosmic abundance towards a lower value
poses stronger constraints on the population of carbonaceous materials.
1.
UV extinction: FUV rise, UV
bump
Observational constraints:
UV bump: Constant peak
position, variable width. Absorption feature.
No correlation between FUV
rise and UV bump.
Note: Other materials are
expected to contribute to the FUV and UV rise.
Materials studied in the
laboratory: HAC, QCC, PAHs, Coals
Laboratory studies +
model(s): interpret observational constraints
· Aromatic
materials: p - p* transitions (bump); s - s* transitions
contribute to the FUV rise.
· A class of
nano-sized carbon materials meets the observational constraints. These
materials are generated from UV-processed HAC (various doses of UV processing).
If present, PAHs should contribute to the FUV rise + UV bump.
Problems/Future studies:
explain lines–of-sight without FUV rise. Contribution of scattering to the FUV
rise (effect of size distribution)
Search for the spectral
signature in the UV of PAHs with space-based observatory (HST).
2.
DIBs (Diffuse
Interstellar Bands): about 200 absorption bands in the NUV – NIR range.
Observational constraints:
Constant peak position and
width
Correlation with reddening
No (loose) correlation
between most of the bands
~2 sets of bands according
to band width (narrow, broad)
The carriers must be
abundant.
Some bands are also observed
in emission.
Materials studied in the
laboratory:
many (C-based candidates)
Current consensus:
molecular, gas-phase carriers
Potential candidates: PAHs
(neutral, ions); Fullerenes (C60+), C-chains (C7-)
Most laboratory studies
using Matrix Isolation Spectroscopy (MIS) of molecules, ions and radicals.
Recent: cold ions/molecules
are isolated in the gas phase (jets or molecular beams + depletion spectroscopy
or high-sensitivity direct absorption techniques)
PAH cations seem to meet the
general characteristics for the broad DIBs.
Future studies/Needs: gas-phase spectroscopy in jets (build a data base); search for new candidates according to stability criteria (radicals, dehydrogenated species in ion traps).
3.
ERE: Extended Red
Emission
Materials studied in the
laboratory:
HAC: recently excluded as primary
carrier (Photoluminescence yield is too
low; the bandwidth is too large when excited in the UV);
QCC: exhibits the best
properties among the carbonaceous materials studied to date. Photoluminescence
yield is still too low for the observed luminescence in the ISM.
Size effects studies on
silicon materials show that silicon nano crystals appear to meet all the
observational constraints (either in the isolated form or embedded in a larger
amorphous grain).
Future studies/Needs:
Spectroscopy of silicon nanocrystals embedded in amorphous (carbon, …) grains,
PL yield of QCC at various excitation energies and at various temperatures, PAH
ions?
Observational constraints:
spectral agreement
Materials studied in the
laboratory:
(small) PAHs: neutrals,
ions; MIS, few gas-phase
Coal (solid)
QCC (films: non-isolated
nanoparticles, 5-15 nm)
HAC (films: non-isolated
nanoparticles, 5-30 nm)
Future studies/Needs:
To account for the
excitation mechanism based on transient heating, small species (i.e., less than
about 1000 carbon atoms) need to be involved. On the other hand, small PAH
cations (less than 32 C atoms) cannot explain alone the observations.
Therefore, the gap between the molecules and solid studied so far needs to be
explored. Study the size effects on the vibrational and electronic
properties.
In the case of PAHs, study
of dehydrogenated species. Laboratory measurements of electronic recombination
rates of PAH cations. In general, a proper evaluation of the charge state of
PAHs in the ISM using a combination of laboratory studies and refined
models.
Note: The 3.53 and 3.43 µm
emission bands indicate the presence of nanodiamonds in some CS environments.
More laboratory studies are needed to evaluate the contribution of these
particles in the visible and the IR.
5.
3.4 µm: IR absorption
band. Materials containing aliphatic carbon
Observational constraints:
absent in dense regions (destroyed)
Laboratory studies:
UV-processing destroys C-H
Re-hydrogenation (H atoms)
Explore the
connection between aliphatic and aromatic materials.
C. Proposal for a review paper
From the working group on carbon-based materials, ISSI, May 8-12, 2000
Title: Status and perspectives of current research on carbon-based analogs of cosmic materials
Time schedule: draft early
November 2000, finale version: December 2000
Size: Approximately 30 pages
(TBD) + references
Coordinator: Ph. Bréchignac
Authors: Allamandola, Baratta,
Bréchignac, Guillois, Joblin, Lequeux, Mennella, Mutschke, Reynaud, Salama,
Wada
·
Introduction (Salama)
·
General Constraints (elemental abundances, self-consistency) (Lequeux)
·
Production Techniques in the Laboratory (Mutschke, Wada)
·
Influence of Processing (Baratta, Mennella)
·
The UV Bump and the FUF Rise (Mennella, Mutschke)
·
The DIBs (Bréchignac, Salama)
·
The UIBs (Joblin, Guillois, Allamandola)
·
The 3.4 µm Feature (Mennella)
·
Perspectives of New Experiments (Bréchignac, Joblin, Reynaud, Salama)
·
Outlook and Conclusions (Reynaud)
Report
of working group on "Silicon-based materials"
Q1:
How to produce the silicon-based materials?
(i)
Sol-gel
techniques
Range of composition
(MgO-SiO2 ratio well-defined)
Combination of three steps
(hydrolysis, condensation, evaporation, densification)
Key parameters for the
production: Stoichiometric ratios, Chemical environment (would be especially
important for formation of Fe-rich silicates)
Results: Optical properties
at 10micron feature (n(Si-O)) depend on
Mg/SiO2 ratio;
Annealing behaviour (crystallization temperature
depends on Si-OH bonding
because of the catalytic influence by changing the
viscosity)
Advantage: Production of
well-defined materials
Disadvantage: Not related to
gas-phase condensation but contains elements of
astrophysically interesting
chemical pathways, Time-consuming technique
(ii)
Production by
laser ablation
Advantage: Straightforward
technique; Condensation from the vapour phase
Disadvantage:
Production of inhomogeneous samples
(iii)
Laser pyrolysis
Advantage: Production of a
large variety of materials possible (silicon nanoparticles, carbides, nitrides,
carbon nanoparticles; control of reaction conditions possible); production of
size-selected particles possible; chemical pathways important for astrophysical
conditions (more radicals compared with ions observed, no walls)
Disadvantage: Material
handling difficult (especially silicon oxides)
(iv) Production of clean crystals (special furnace
for the production)
-
Limitation of different techniques (Reflection vs. powder techniques,
thin section)
-
Synchrotron facility (Bessy II)
-
Check the PL of nano-sized materials
-
High-resolution electron microscopy
-
Atomic Force Microscopy and time-of-flight mass spectroscopy to
determine size distribution of small particles
-
Raman spectroscopy (molecular water)
-
Mass spectroscopy to find out the formation routes
-
EXAFS: short scale order
Silicon nanoparticles as
explanation for ERE (size counts - quantum confinement,
dangling bonds must be
passivated), Wavelength depends on size on grain (smaller
particles PL with higher
frequencies), only crystalline materials give PL curves with the
right widths, band gap
increases for smaller particles
Q4:
Annealing processes (temperatures, irradiation; Control the atmosphere!)
-
Difference if Si-OH groups are present
-
Different Mg/Fe ratios (no final answer reached; contradicting results
in the literature)
-
Different structures of bulk materials and nano-sized powders
- Ion bombardment will give different results depending on
energies
Q5: Surface reactions under conditions of the ISM (Accretion vs. reaction-limited chemistry)
There is a large difference
between crystalline structures and polycrystalline/amorphous surfaces concerning the tunneling
probability. Thermal activation plays an important role.
FeSi and FeSi, SiC should
be investigated in the form of nano-sized particles.
B. Astrophysical problems and laboratory role
1.1 Crystalline silicates
·
Mg rich and Fe poor (olivines and pyroxenes)
·
circumstellar
·
separate grain populations in old stars
·
abundance in outflow sources: 10 – 15 %
·
crystalline silicates can be highly abundant in disk sources (up to 75
%)
·
band shapes in outflow and disk sources are somewhat differences
·
high abundance of crystalline silicates implies coagulation
·
crystalline silicates are produced in proto-planetary disks. They are
found at large distance from the star (low T)
1.2 Amorphous silicates
·
Interstellar silicates are amorphous
·
Most circumstellar silicates are amorphous
·
Low mass loss rate AGB stars have amorphous silicates with band shapes
that deviate from interstellar ones
· There is evidence
that high mass loss rate AGB stars produce amorphous silicates that are similar
to interstellar ones
· Silicates in
massive YSO’s are amorphous
· Young proto-stars
have amorphous silicates, “old” proto-stars have am. + cryst. silicates
2. Questions
·
Are crystalline and amorphous silicates in thermal contact in young
stars, Hale-Bopp ?
Answer: through
modelling
·
Do crystalline silicates become amorphous due to ion bombardment... ?
...or viceversa.
How does it depend on temperature and energy and fluxes of ions ?
Answer: through
laboratory experiments (check literature)
· Are GEMS truly
interstellar ? What is the percentage of GEMS containing forsterite inclusions?
Answer: isotope analysis
- ask John Bradley (second part of question)
·
What is the spatial distribution of amorphous and crystalline silicates
?
Answer: model + high
angular resolution observations
·
Why are crystalline silicates always Mg-rich and Fe-poor ?
Answer: condensation
experiments + chemical network modelling
·
Is it possible that amorphous silicates contain small islands of
crystalline silicon ?
Answer: experiment +
fluorescence and electron microscopy measurements
· What is the
spectroscopic difference between and Fe-Mg amorphous silicates and an Mg-rich
amorphous silicates with Fe inclusions ?
Answer: experiment
· Why are the
observed crystalline silicate band widths smaller than those observed in the
laboratory ?
Answer: low temperature
laboratory data, models on size/shape effects (?)
·
Is it possible to expel Fe from silicates by thermal annealing ?
Answer: experiment (check literature)
· Laboratory
spectra of hydrous silicates + observational characteristics of the 90 mm band are needed
· Identification of
unidentified bands in oxygen-rich sources
Answer: experiments and comparison with (ISO)
observational data
C. Proposal for a review paper (Astronomy and
Astrophysics Review)
Time schedule (submit the individual chapters at the end of September)
30 pages plus references
Main Editors: L. Colangeli, Th. Henning
Authors: Huisken, Reynaud, Ledoux, Guillois, Jessberger, Waters, Molster, Rietmeijer, Bradley, Jaeger, Fabian, Mutschke, Pirronello, Biham, Manico, Vidali, Brucato, Mennella, Rotundi, Palumbo, Jones, Koike
1.
Introduction (Colangeli)
2.
Elemental abundance and depletion in ISM (Henning, Jones)
3.
Observational constraints from infrared spectroscopy (Waters)
4.
Interplanetary Dust Particles
and Meteorites (Jessberger)
5.
Production methods in the laboratory (Brucato)
6.
Analytical techniques (Jaeger)
7.
Spectroscopy (Mutschke)
8.
Annealing processes (Fabian)
9.
Surface processes (Pirronello)
10.
Difference between bulk materials and nano-sized grains (Huisken)
11.
Other silicon-based materials (Henning)
12.
Conclusions and outlook (Colangeli)
Report
of working group on "Ices"
· General items
- In the laboratory ices are accreted,
from the gas phase, on a substrate: is this the right way to simulate
astrophysical ices that, with a few exceptions, are formed on grains by
reactions of the forming atoms?
- Is the chemistry induced by ice
formation and/or by processing (UV, ions, thermal, etc..) dependent on the
substrate, i.e. silicates vs
carbonaceous cores?
- There is any evidence of ice
processing in space? The case of the
XCN feature
- We have a poor knowledge of the
optical constants of ices (in particular of processed ices) that are often fundamental to compare laboratory
with astronomical spectra (in particular ices in the Solar System).
- Which is (are) the
"unprocessed" ice mixture(s) we have to start with to study its
(their) processing (UV, ions, thermal _….?)
· Recommendations
It would be useful to "measure", in the laboratory, relevant parameters in
order to scale results obtained at a given temperature in a given time to
temperatures and times relevant to the different space conditions. This has
been done in the past for e.g. water
ice crystallization and sublimation of "pure" ices. It would be
useful to have similar results for processes such as segregation (e.g. of CO2
in water/methanol mixtures), temperature-dependent shift in peak position and
profile changes (e.g. of the XCN and NH4+ bands).
When possible it would be useful to use
substrates with different chemical compositions and roughness (e.g.
carbonaceous and silicates). In the future it could be possible to
perform experiments with single particles to study surface chemistry as a
function of substrate chemical composition.
- Possible evidences for processing in space:
-- lack of the 3.4 micron feature in dense
clouds!!
-- XCN feature
-- 6.8 micron feature (NH4+ )
Where
methanol is abundant energetic processing should be less relevant. Where it is
underabundant the question arises: is it such because it is destroyed by
processing or it is intrinsically
lacking?
"Primitive
mixtures"
Very hard to say which they are. Then attempts
have to be done to try to reproduce the entire observed spectra after
processing of chosen mixtures. Alternatively one can be confident that a band
may be due to processing after it has been produced not only after a single
choice of starting conditions but after
a number of different experiments.
- Suggested Experiments
Sulphur containing mixtures (e.g. deposition and processing of H2O:CS
frozen mixtures)
Residues (IR and molecular analysis)
Make
the same experiment at different temperatures (e.g. 10 K and 50 K)
Thermal formation of XCN containing species
Determine upper limit for formyl radical
One of the major questions in the formation of ices is their production
mechanism, which may proceed either via grain surface chemistry or by accretion
of simple molecules with subsequent
processing by cosmic rays, UV photolysis, or a combination of both.
Future grain surface reaction experiments will elucidate which molecules
are formed by the reaction of atoms and
molecules on grain surfaces. Important key molecules to study are CO2 (formed
by the reaction CO+O), CH3OH (formed by hydrogenation of CO), and others. From
those experiments crucial parameters can be derived, such as reaction rates and
activation barriers. The formation of molecules such as CO2, CH3OH, CH4, H2CO,
HCOOH, and others by energetic processing has been already extensively studied
in different laboratories. A quantitative comparison between ion bombardment
experiments and UV photolysis on the same mixtures are however still warranted.
Energetic processing as performed in the laboratory (by H discharge UV
lamps/MeV proton accelerators and keV ion guns) seems to be representative of
processes which may be occurring in
space. In laboratory simulations, two photon processes can be excluded
due to the long timescale between successive impinging events. However, whether
the action of photons and energetic particles on laboratory ice is
representative of interstellar conditions has yet to be demonstrated.
Though laboratory experiments on irradiation of ices lead to the
formation of many complex organic
molecules, these experiments may not be representative of conditions in the
dense interstellar clouds. We do not have any spectroscopic evidence of the
presence of complex organics such as
acetonitrile, etc. in astronomical IR spectra.
However it can not be excluded that such large organics are present at a level below ~1% ,
where they would remain undetected.
The large extinction of the shell around high mass embedded protostars,
definitely attenuates the UV flux from the protostar efficiently. Therefore,
the correct dose of energetic processing in such regions has to be revisited,
by using the information of atomic emission lines in the NIR and FIR and other
line of sight parameters.
However it can not be excluded that UV irradiation can penetrate to some
extent in the general dense medium due to the inhomogeneous, filamentary
structure of interstellar clouds.
The working team supports the integration of a grain/gas chemical model which is based on recent IR and radio
observations. An important question is the complexity of molecules which can be
reached in the solid state and in the interstellar gas and how are gas and
grain chemistry interlinked. The desorption of simple molecules such as CH3OH
from the grain surface may act as seeds to drive a gas phase complexity, which
requires only hot temperature. Those species formed in the gas may re-accrete
on the grain.
An important test of the relevance of energetic and thermal processing
would involve experiments which produce complex organics from simple molecules.
These samples should also be studied by GC-MS in order to define the products
which may be sublimed in the gas and be detected by radio observations.
The question raised in the last meeting about variation in ion flux in
different interstellar regions has been discussed, but the constant H3+ column
density, a tracer of cosmic rays, argues against any strong deviations in
molecular clouds (van der Tak et al. 1999).
One of the major questions is the absence of N and S containing species
in ices, as well as transient species (such as HCO). Currently identified N-containing species are NH3 and XCN. The
only sulphur containing species currently detected is OCS, whereas in the gas
phase species such as H2S, H2CS, SO, SO2 and CS are observed.
Most of the N is believed to be
in the form of N2 in the interstellar gas, and could condense out in a
substantial fraction on the grain surface.
Experiments which could improve our knowledge on this N and S chemistry
would be ice mixtures of e.g. processed H2O/CS and H2O/N2, which may lead to
several S- and N-containing species.
The determination of upper limits of nitriles, isonitriles and hydrogenated
N-compounds from astronomical spectra could provide some information on the N not incorporated into N2 and NH3.
An important issue is to study the differences in the ice composition in
different environments, such as high-mass, low-mass and field stars. Future
ground based observations with the VLT will allow us to constrain the
abundances (or upper limits) of molecules such as CH3OH, XCN, OCS, etc in low mass protostars which will constrain
the difference in chemistry in those environments.
The key molecules: CO2, CH3OH, XCN
Observational constraints:
-Abundance of solid CO2 is 15-20% relative to water ice
towards field stars and low mass protostellar objects whereas the range is 15-40% relative to H2O towards
high mass protostars.
- Solid methanol is abundant towards high mass protostars (up to 35%
relative to water ice) while is almost absent (< 3% relative to H2O)
towards field stars and low mass protostars.
- Up to now the detected icy
species are relatively simple molecules formed only by H, C, N, O, and S. Are
all of the other atoms embedded in the refractory dust component (if yes, in
which form?) or is there a chance to detect them in the icy component?
C. Working program for members
of the ice working group:
Objective: G values for CH3OH destruction, CO and CO2 formation
Common experiment:
IR spectroscopy /UV photolysis and ion bombardment of:
CH3OH (12 K, 1000 Ang thick)
AMES (UV + filters + deposition at 125 K)
CATANIA (UV + 30 keV He+, 60 keV Ar++)
GODDARD (UV + 0.8 MeV H+ and two different temperatures)
LEIDEN (UV + mixtures with water+Ar matrix)
Results will be compared and a paper will be prepared during a next ISSI
Workshop.
Participants
to the Workshop:
|
Name |
Address |
E-mail |
|
G. Baratta |
Osservatorio Astrofisico
di Catania Via S. Sofia 78, 95123
Catania, Italy Tel.: +39 95 7332212 Fax: +39 95 330592 |
|
|
M. Bernstein |
Mail Stop 245-6 NASA Ames Research Center Moffet Field, CA –94035-
1000 USA Tel.: +1 (650) 604 0194 Fax: +1 (650) 604 6779 |
|
|
P. Brechignac |
Laboratoire de
Photophysique Moleculaire, Bat.210, Universitè de
Paris-Sud F 91405 Orsay Cedex Tel.: +33 1 69 15 67 79 Fax: +33 1 69 15 67 77 |
|
|
J.R. Brucato |
Osservatorio Astronomico
di Capodimonte Via Moiariello 16, 80131
Napoli, Italy Tel.: +39 81 298384 Fax: +39 81 456710 |
|
|
L. Colangeli |
Osservatorio Astronomico
di Capodimonte Via Moiariello 16, 80131
Napoli, Italy Tel.: +39 81 298384 Fax: +39 81 456710 |
|
|
P. Ehrenfreund |
Raymond and Beverley
Sackler Laboratory for Astrophysics at Leiden Observatory, PO Box 9513 2300 RA Leiden, The
Netherlands Tel.: +31 71 5275812 Fax: +31 71 5275819 |
|
|
O. Guillois |
CEA, CE- Saclay SPAM Bat. 522, 91191 Gif/Yvette Cedex
France Tel.. +33 1 69 08 91 87 Fax: +33 1 69 08 87 07 |
|
|
Th. Henning |
Friedrich Schiller
University Jena Astrophysical Institute
and University Observatory Schillergaesschen 3, 07745
Jena Germany Tel.: +49 3641 947533 Fax: +49 3641 947532 |
|
|
F. Huisken |
Max-Planck-Institut f. Stroemungsforschung, Bunsenstr. 10, D- 37073 Goettingen,
Germany Tel.: +49-551-5176-575 Fax: +49-551-5176-607 |
|
|
C. Jaeger |
Friedrich Schiller
University Jena Astrophysical Institute
and University Observatory Schillergaesschen 3, 07745
Jena Germany Tel.: +49 3641 947533 Fax: +49 3641 947532 |
|
|
E. Jessberger |
Institut fuer Planetologie Wilhelm Klemm Str. 10, D- 48149 Muenster Germany Tel.: +49-251-833-3492 Fax: +49-251-833-6301 |
|
|
C. Joblin |
CESR-CNRS BP4346-, 9, Av. Du Colonel
Roche, 31028 Toulouse Cedex 04-
France Tel.: office
+33-5-61-55-86-01 Tel.: lab +33-5-61-55-77-53 Fax: +33-5-61-55-67-01 |
|
|
A. Jones |
Institut d’Astrophysique
Spatiale Universite Paris XI, Bat. 121 91045 Orsay, Cedex, France Tel.: +33 1 69 85 86 47 Fax: +33 1 69 85 86 75 |
|
|
A. Kouchi |
Institute of Low
Temperature Science, Hokkaido University, Sapporo
060-0819 Japan Tel.: +81-11-706-5500 Fax: +81-11-706-7142 |
|
|
V. Mennella |
Osservatorio Astronomico
di Capodimonte Via Moiariello 16, 80131
Napoli, Italy Tel.: +39 81 298384 Fax: +39 81 456710 |
|
|
F. Molster |
Astronomical Institute
“Anton Pannekoek”, University of Amsterdam, Kruislaan 403, NL- 1098 SJ Amsterdam, The
Netherlands Tel.: Fax: |
|
|
M. Moore |
Astrochemistry Branch,
Code 691 NASA’s Goddard Space
Flight Center, Greenbelt Rd., Greenbelt, MD 20771 Tel.: Fax: |
|
|
H. Mutschke |
Friedrich Schiller
University Jena Astrophysical Institute
and University Observatory Schillergaesschen 3, 07745
Jena Germany Tel.: +49 3641 947533 Fax: +49 3641 947532 |
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M.E. Palumbo |
Osservatorio Astrofisico
di Catania Via S. Sofia 78, 95123
Catania, Italy Tel.: +39 95 7332261 Fax: +39 95 330592 |
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V. Pirronello |
D.M.F.C.I. Università di Catania, Viale A. Doria, 6 95125 Catania, Italy Tel.: +39 095 7382805 Fax: +39 095 332231 |
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C. Reynaud |
Service des Photons,
Atomes et Molecules, CEA-Saclay- 91191
Gif/Yvette, Cedex, Tel.: +33 1 69 08 69 16 Fax: |
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F. Salama |
NASA Ames Research Center Space Science Division MS: 245-6 Moffett Field, CA
95035-1000 USA Tel.: 1-650-604 3384 Fax: 1-650-604 6779 |
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S. Schlemmer |
TU Chemnitz, Inst. fuer
Physik Gasentladungs – und
Ionenphysik D – 09107 Chemnitz, F.R.G. Tel.: +49 371 531-3049 Fax: +49 371 531-3103 |
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W. Schutte |
Leiden Observatory,
Raymond and Beverley Sackler Laboratory for Astrophysics, 2300 RA Leiden, The
Netherlands Tel.: +31 71 275890 Fax: |
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G. Strazzulla |
Osservatorio Astrofisico
di Catania Via S. Sofia 78, 95123 Catania,
Italy Tel.: +39 95 7332213 Fax: +39 95 330592 |
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A.G.G.M. Tielens |
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S. Wada |
University of
Electro-communications 1-5-1, Chofu-gaoka,
Chofu-shi, Tokyo, 182-8585, Japan Fax: +81-424-43-5563 |
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N. Watanabe |
Institute of low
temperature science, Hokkaido University, N18 – W8, Kita-Ku, Sapporo
060-0819 Japan Tel.: +81-11-706-5501 Fax: +81-11-706-7142 |
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R. Waters |
Astronomical Institute
“Anton Pannekoek”, University of Amsterdam, Kruislaan 403, NL- 1098 SJ Amsterdam, The
Netherlands Tel.: Fax: |