Center for Atomic, Molecular, and Optical Physics 1989 Technical

C INS^ Of STAND & TECH R I A111Q4 OblbMS NATIONAL INSTITLTTE OF STANDARDS ^ TECHNOLOGY Research Information Center Gaithersburg, MD 20899 !* 5 NIST PUBLICATIONS ' ' ‘ . NISTIR 89-4184 NAT-L INST. OF STAND 4 TECH R.I.C. A111D3 3Sb7E7 Center for Atomic, Molecular, and Optical Physics m 1989 89-4184 . Technical Activities 1989 C.2 NATIONAL INSTITUTE OF STANDARDS & TECIDTOLOGY Research Information Center Gaithersburg, MD 20899 Image of a cloud of laser cooled Be'^ ions confined in a Penning trap. The spherically symmetric cloud (partially illuminated by three laser beams) is arranged in a liquid-crystalline phase of eleven concentric shells. This cloud contains approximately 15,000 ions and is 550 microns in diameter. Transitions from disordered to ordered states are being studied in cooled ion clouds in the Time and Frequency Division of the Center for Atomic, Molecular and Optical Physics. NISTIR 89-4184 Center for Atomic, Molecular, and Optical Physics 1989 Technical Activities December 6-7, 1989 Katharine B. Gebbie, Acting Director Center for Atomic, Molecular, and Optical Physics National Measurement Laboratory U.S. DEPARTMENT OF COMMERCE, Robert A. Mosbacher, Secretary National Institute of Standards and Technology, Raymond G. Kammer, Acting Director f It L I I j» 1 t";,'! »'?***'*' VI. \ • : '.a ^ k “• , * :-v-r" '/r! 5?,. ' ' ^ ' • :'l ' i ® c, \.T'' ' *V ’t • I ’ . ^ '>'•• » 't -''"if-'f , r Vt ...A..;’i ' I'-’ \ iiT-ciofl ' ' J f/fiCiiiysR ,\'i; ^ ... ly !. > . ABSTRACT This report summarizes the research and technical activities of the Center for Atomic, Molecular and Optical Physics (CAMOP) during the Fiscal Year 1989. These activities include work in the areas of fundamental constants, radiation physics, surface science, molecular spectroscopy, electron and optical physics, atomic and plasma spectroscopy, time and frequency, quanttun metrology, and quanttun physics Keywords: Astrophysics; atomic physics; calibrations; chemical physics; fundamental constants; gravity; laser physics; molecular physics; optical physics; plasmas; radiation; solid state physics; spectroscopy; standards; surface science; time and frequency; wavelength standards. iii INTRODUCTION This report is a summary of the technical activities of the National Institute of Standards and Technology (NIST) Center for Atomic, Molecular, and Optical Physics (CAMOP) for the period October 1, 1988 to September 30, 1989. The Center is one of the four technical operating units in the National Measurement Laboratory. The summary of activities is organized into eight sections, one for the technical activities of the Center office staff, and one each for the seven divisions of the Center. Each division tells its own story in its own way. In general, there is an overview followed by a series of short reports on current projects. Then the publications, invited talks, committee participation, and some of the technical interactions during the year are listed. To obtain more information about particular work, the reader should address the individual scientists or their division, c/o Center for Atomic, Molecular and Optical Physics, B160 Physics Building, National Institute of Standards and Technology, Gaithersburg, Maryland 20899. IV TABLE OF CONTENTS Abstract iii Introduction iv Fundamental Constants Data Center (570) 1 Laser-Cooled and Trapped Neutral Atoms 9 Electron and Optical Physics Division (571) 17 Atomic and Plasma Radiation Division (572) 63 Surface Science Division (573) 89 Molecular Physics Division (574) 143 QuantTom Metrology Division (575) 185 Time and Frequency Division (576) 213 Quantum Physics Division (577) ! . 267 Acronyms 353 V *^7 U- i i - - :' -. -. : ' . i-.? --o' .; i s I U- 'i- \%‘'‘!ii •otv.'* '> ' '*' '' ' ' '- 1 . ''V* f , :iS: V. , . - ,...,; :. ’r../ . ^?.J::r. lylil: i ' ' I -w. ) r . , FUNDAMENTAL CONSTANTS DATA CENTER B. N. Taylor OBJECTIVES; (1) To provide an international information center on the fundamental physical constants and closely related precision measurements analyze the consistency values (FCPM) ; (2) to of measured of the constants in order to test fundamental physical theory and to obtain sets (or subsets) of "best" or recommended values of the constants for international use; (3) to organize conferences or sessions at conferences on FCPM; and (4) to contribute to the work of various international and national committees and organizations active in the FCPM (or a closely related) field. Two other major objectives are (5) to serve as Chief Editor of the Jouxmal of Research of the National Institute of Standards and Technology (J . R. NIST); and (6) to administer the NIST Precision Measurement Grant (PMG) program. MOTIVATION: The fundamental constants have long been of importance to NIST because of their close relationship to precision measurements, basic measurement units such as the ampere, volt, and ohm, fundamental physics, state-of-the-art measurement technology, theoretical calculations, and the compilation and analysis of critical reference data. One of the aims of the Data Center is to provide assistance and guidance in the FCPM area to both NIST and university scientists, for example, to advise them on the potential impact of the experiments they are considering carrying out and to keep them informed of related work underway in various laboratories throughout the world. NIST PMG's are awarded to scientists in U.S. academic institutions in order (1) to promote research in the FCPM field and train future measurement-oriented scientists; and (2) to foster contacts between NIST scientists and those researchers in the academic community who are actively engaged in such work. VThile NIST has much FCPM research underway, there is considerable expertise and relevant work in U.S. colleges and universities. The PMG program taps this reservoir and fosters the training of students who might eventually become NIST staff by awarding grants to outstanding academic researchers ACTIVITIES: These include (1) keeping apprised of and maintaining a complete reprint collection of the latest accomplishments throughout the world in FCPM; (2) carrying out least-squares adjustments of the fundamental constants to obtain sets or subsets of recommended values; (3) par- ticipating in the work of national and international groups, for example, the Committee on Data for Science and Technology (CODATA) Task Group on Fundamental Constants, the NAS/NRC Advisory Committee on Fundamental Constants and Standards, the Consultative Committee on Electricity (CCE) and the American Physical Society Topical Group on Fundamental Constants and Precise Tests of Physical Laws; (4) organizing FCPM conferences or FCPM sessions at conferences; (5) answering inquiries from both within and without NIST relating to the FCPM field; (6) soliciting papers for J. R. NIST and overseeing its publication; and (7) awarding two new $30K/year PMG's each year and renewing four existing $30K/year PMG's. 1 . ACCOMPLISHMENTS: The work emphasis in FY 89 has been on selecting values of the Josephson and von Klitzing constants (Kj and Ry^) to serve as the basis for new international representations of the volt and ohm to come into effect starting January 1, 1990; to document fully the selection process; and to help NIST inform science, commerce, and industry, but most especially the users of its electrical calibration services, about the new representations and how to bring standards and instruments into conformity with them. (Note that it is assumed Kj 2e/h and = h/e^ where e is = , the elementary charge and h is the Planck constant.) This was done by serving as a principal member of the CCE's Working Group on the Josephson Effect, Coordinator of the CCE's Working Group on the Quantum Hall Effect, NIST representative to the CCE, preparing articles, and delivering talks (see lists which follow). The calibration reports for NIST voltage standard calibrations, including the information sheet, were rewritten. A detailed plan for carrying out the next least-squares adjustment of the fundamental constants was worked out in collaboration with T. J. Quinn, Chairman of the CODATA Task Group on Fundamental Constants, and E. R. Cohen, a principal member of the Task Group. It is to be completed in early 1993 and published simultaneously in Rev. Mod. Rhys, and J. Rhys. Chem. Ref. Data as agreed by the editors of both journals. The FCDC assisted S. E. Chappell, Chief of the NIST Office of Standards Management, in revitalizing ISO (International Standardization Organization) Working Group 3, "Expression of Uncertainties" and assumed responsibility for representing NIST and the U.S. on the Working Group. During FY 89, a three pronged approach to revitalizing the J. R. NIST was initiated: (1) papers were solicited via memoranda to the NIST staff. Center Directors, and Division Chiefs, plus numerous personal contacts and wide distribution of revised instructions for manuscript preparation; (2) the appearance of J. R. NIST was improved via a new, modern cover color and typography: and (3) an effort was made to increase subscriptions via a strong advertisement campaign. Additionally, the Board of Editors was reconstituted and its charter modified and updated. Steven Chu, Stanford University, and Edward E. Eyler, University of Delaware, were the two new recipients of PMG's in FY 89. Chu's project, "Precision Optical Spectroscopy of Positronium, " will determine the 1 ^S - 2 ^S inteirvai in positronium via two photon laser spectroscopy with a relative uncertainty approaching 1 part in 10^°,

Load more