Intermolecular interactions for extreme states of substance
Experimental study of intermolecular interactions specific to extreme states of substance
Tech Area / Field
- PHY-ANU/Atomic and Nuclear Physics/Physics
3 Approved without Funding
Keldysh Institute of Applied Mathematics, Russia, Moscow
- Russian Academy of Sciences / Space Research Institute, Russia, Moscow
- Stockholm University / Atomic Physics Department, Sweden, Stockholm\nStockholm University / Department of Physics, Sweden, Stockholm\nKungliga Tekniska Hoegskolan / Stockholm Physics Centre, Sweden, Stockholm
Project summaryThe project goal is exploration of the intermolecular interactions for conditions specific to extreme substance states and making up on this basis of the experimental data bank. Measurements of cross-sections and transition probabilities are proposed for particles in either basic state or electronically vibrated ones.
Adequate planning and carrying out of experiments with the hypervelocity flows as well as their successful technological utilization is hardly possible without the qualitative understanding and the quantitative information about the elementary processes in collisions of particles under the extreme conditions (high temperatures and pressures). Development of many branches in physics and technology e.g. gas dynamics, thermo-physics, chemical physics, gas discharge physics etc. requires studies of atomic particles (atoms, molecules and ions) under the extreme conditions. The reliable data on the substance properties is mostly available for the temperatures below one thousand of Kelvin and the pressures lower then hundreds of kilobars. The conventional experiments (studying the equilibrium and kinetic properties of the atoms and molecules) as a rule give no knowledge on the substance properties under the extreme conditions. As often as not the laboratory experiment for such conditions is just impossible leaving the only way to scrutinize the phenomena by means of the mathematical simulation Information on the electronic vibrational states of atoms and molecules featuring extreme conditions of substance and exploration of interactions involving particles in both basic and exited states need experiments, which would generate these states via the most direct technique. This information is provided by experiments using the molecular beam technique. The molecular beam technique is highly interesting and ideally accomplishes collision of a pair of the atomic particles with controllable values (and directions) of the velocities and the colliding particles’ quantum states before and after the collision. Besides the fast molecular beam technique (the beam energy of ~1 keV) makes it possible to explore processes with the interaction energies within 0.1-10 keV typical for the temperatures of 1,000-10,000 Kelvin and high pressures.
It's been a long time since the fast molecular beams scattering technique was the base for studies of the elastic collisions of atomic particles to calculate their interaction potential. Transfer from studying of the only scattering act to definition of the scattered particle energy permits to start investigation of the electronic-vibrational states of atoms and molecules within a wide range of the collision velocities and the conditions specific for the strong pulse effect in particular.
The major work volume of the project is concentrated on experiments measuring the intermolecular interaction cross-sections of atoms and molecules involving the electronic-vibrational excitation with the fast molecular beams scattering technique and making up of the data bank on this basis. Calculation of substance properties for the extreme conditions is also provided.
The project plans the following works:
1. Analysis of the present state of the issue by the available publications.
2. Modernizing of the experimental facilities for studies of the intermolecular interactions including the electronic-vibrational states of atoms and molecules by the fast molecular beams scattering technique.
3. Development of software to control operation of the facilities and process the obtained information.
4. Making of measurements to study the electronic-vibrational excited states of atoms and molecules. Exploration of collisions for the inert gas systems (He, Ne, Ar, Kr, Xe), with N2, O2, CO2 molecules is supposed for the first stage.
5. Numerical simulation of substance properties for the extreme conditions.
The gained results would be of great importance in studies of the substance properties under extreme conditions.
In the frameworks of the proposed project we expect to achieve the following results:
– Modernization of a unique instrument for studies of atomic and molecular interactions with the fast molecular beam scattering technique using multi-particle time-position- sensitive detector providing synchronous detection of multi-particle elementary processes.
– Measurement of the differential cross-sections of collision and excitation for various electronic vibrational atomic and molecular states as well as study of the differential cross-sections of excited atoms and molecules with the collision energies corresponding to conditions of the hypersonic flows, high temperatures and pressures.
– Filling of database on the differential cross-sections of excitation for different electronic vibrational states of atoms and molecules and differential cross-sections of collision excitation for electronically vibrationally excited atoms and molecules with the collision energies corresponding to conditions of the hypersonic flows, high temperatures and pressure.
– Calculation of substance properties for the extreme conditions.
The proposed project participants have sufficient qualification for the experimental work in the field of atomic physics and the molecular beams in particular. It has passed many years since experiments using the molecular beam technique had started at SRI of RAS IAM of RAS and ICP of RAS. In particular they have researched the interaction of metastable helium atoms with the helium in its basic state. Nowadays the project participants work with two operating experimental installations using the fast molecular beam scattering techniques and requiring relatively slight upgrading to carry out the project work. It should be noted at this point that the fast molecular beam installations are very complicated and expensive, as they need high vacuum, special beam producing mass-separating techniques, specialized detectors of particles, and complex installation control and data processing systems. Since the facilities only need small upgrading it would take small expenses to obtain very interesting results.
The foreign collaborators’ part in accomplishing of this project includes cooperative planning of the experiments, interpreting of the data, information exchange in the frameworks of the project, producing of comments to the technical reports dispatched by the project participants for the ISTC and to other scientific publications. Collaborators’ participation in the mutual publications on the project results is also implied.
The project tasks are fulfilled both by the experimental measurements and the mathematical modeling technique for the substance properties.
The planned works are partially based on the upgraded experimental installations of the project participants. We suppose to take advantage of the experience achieved in these fields either in this county or abroad.
The installations would be tested via comparison of their data against the available experimental ones. Much of the research techniques used in the project are original.
Interpretation of the obtained results is facilitated by the experience gained by the project participants when interpreting measurements of the scattering cross-sections and restoration of the interaction potentials.
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