Two Postdoctoral Research Appointments will be made in the Atomic and Molecular Physics Group at the Jet Propulsion Laboratory, California Institute of Technology. Details for each post are given in the following.

APPOINTMENT 1. The first appointment is as a NASA Postdoctoral Fellow. Work will be in the area of highly-charged ion (HCI) collisions using the HCI Facility in the A&M Physics Group. Quantities measured are (1) absolute electron-HCI excitation cross sections for solar and stellar physics, (2) absolute HCI single- and multiple total charge-exchange cross sections for interaction with planetary upper atmospheres, comets, and circumstellar clouds, (3) HCI-neutral X-ray emission spectra and cross sections (comets), and (4) metastable lifetimes of HCI levels for solar & stellar plasma modeling.

Dr. Ara Chutjian will serve as JPL advisor to the selected candidate. The appointee will be guided to ensure that the research work will results in publications in the refereed literature. Candidates should have a recent PhD in collision physics with a background in working with HCIs, low-energy electrons, and ultrahigh vacuum. Knowledge of electronics and computer interfacing is also highly desirable. The annual starting salary for a recent PhD is $52,000, with funds available for relocation and conference travel. Appointments are for one year, and may be renewed in one-year increments for a maximum additional two years. Applicants must be approved by Dr. Chutjian prior to submitting an official application to the NASA Postdoctoral Program (NPP). To be an approved applicant, please send your research proposal, curriculum vitae, a list of three references (with telephone numbers and postal and email addresses) and any questions by October 1, 2009 to:

Dr. Ara Chutjian
JPL/Caltech, MS 121-104
4800 Oak Grove Drive
Pasadena, CA 91109 USA

Further information on the NASA Postdoctoral Program can be found at http://nasa.orau.org/postdoc/. The relevant Research Opportunity is entitled "Highly Charged Ion Collisions. The application deadline is November 1, 2009.

Representative publications in this area are:

"Measurement of Metastable Lifetimes for Transitions in Fe9+, Fe10+, and Fe13+," S. J. Smith, A. Chutjian, and J. A. Lozano, Phys http://prola.aps.org/pdf/PRA/v72/i6/e062504 . Rev. A 72, 062504 (2005).

"Measurement and Calculation of Absolute Cross Sections for Excitation of the 3s23p 2Po1/2 - 3s23p 2Po3/2 Fine-Structure Transition in Fe13+," S. Hossain, S. S. Tayal, S. J. Smith, J. C. Raymond, and A. Chutjian, http://scitation.aip.org/getpdf/servlet/GetPDFServlet?filetype=pdf&id=PLRAAN000075000002022709000001&idtype=cvips&prog=normal Phys. Rev. A 75, 022709 (2007).

"Absolute Single and Multiple Charge Exchange Cross Sections For Highly Charged C, N, and O Ions Colliding with CH4" N. Djuri?, S. J. Smith, J. Simcic, and A. Chutjian, http://www.iop.org/ej/article/0004-637x/679/2/1661/73728.web.pdf?request-id=3fbd1f56-6efd-40a7-b8b5-f607989b4eaa Ap. J. 679, 1661 (2008).

APPOINTMENT 2. The second appointment is as a Caltech Postdoctoral Scholar in the area of mass spectrometer miniaturization, with emphasis on the detailed trapping behavior of the Paul ion trap with regard to external ion injection, and ion ejection. Work will be carried out in modeling space-charge effects and measurement of accurate rare-gas isotope ratios with 103-105 trapped ions using the JPL supercomputer. This work is expected to lead to the development of miniature mass spectrometer systems for human and robotic planetary exploration.

The successful applicant will also have the opportunity to work in the area of fast (0.5-50 eV), ground-state H- and O-atom collisions with surface-adsorbed molecules. The goals of this work are to measure the reaction channels that are open towards generating larger molecules (understanding the building blocks of life); and to measure absolute reaction yields for each channel.

Candidates should have a recent PhD in collision physics with a background in working with HCIs, low-energy electrons, and ultrahigh vacuum. Knowledge of electronics and computer interfacing is also highly desirable. The annual starting salary for a recent PhD is $52,000, with funds available for relocation and conference travel. Appointments are for one year, and may be renewed in one-year increments for a maximum additional two years. Applicants must be approved by Dr. Chutjian prior to submitting an official application to the Caltech Postdoctoral Scholar Program. To be an approved applicant, please send your research proposal, curriculum vitae, a list of three references (with telephone numbers and postal and email addresses) and any questions by October 1, 2009 to the address given in APPOINTMENT 1 above. The final application deadline is November 1, 2009.

Representative publications in this area are:

"Digitally Synthesized High Purity, High Voltage Radiofrequency Drive Electronics for Mass Spectrometry," R. T. Schaefer, J. A. MacAskill, M. Mojarradi, A. Chutjian, M. R. Darrach, S. Madzunkov, and B. J. Shortt, http://scitation.aip.org/getpdf/servlet/getpdfservlet?filetype=pdf&id=rsinak000079000009095107000001&idtype=cvips&prog=normal Rev. Sci. Instr. 79, 095107 (2008).

"Measurements of Polyatomic Molecule Formation on an Icy Grain Analog Using Fast Atoms," S. Madzunkov, B. J. Shortt, J. A. MacAskill, M. R. Darrach, and A. Chutjian, http://scitation.aip.org/getpdf/servlet/getpdfservlet?filetype=pdf&id=plraan000073000002020901000001&idtype=cvips&prog=normal Phys. Rev. A 73, 020901(R) (2006).

"Formation of Formaldehyde and Carbon Dioxide on an Icy Grain Analogue Using Fast Hydrogen Atoms," S. M. Madzunkov, J. A. MacAskill, A. Chutjian, P. Ehrenfreund, M. R. Darrach, G. Vidali, and B. J. Shortt, http://www.iop.org/ej/article/0004-637x/697/1/801/apj_697_1_801.pdf?request-id=6cefbada-738a-4610-99a2-0018590024cb Ap. J. 697, 801 (2009).

All best,
Ara Chutjian