5 USC 3104 - Employment of specially qualified scientific and professional personnel

(a) The Director of the Office of Personnel Management may establish, and from time to time revise, the maximum number of scientific or professional positions for carrying out research and development functions which require the services of specially qualified personnel which may be established outside of the General Schedule. Any such position may be established by action of the Director or, under such standards and procedures as the Office prescribes and publishes in such form as the Director may determine (including procedures under which the prior approval of the Director may be required), by agency action.
(b) The provisions of subsection (a) of this section shall not apply to any Senior Executive Service position (as defined in section 3132 (a) of this title).
(c) In addition to the number of positions authorized by subsection (a) of this section, the Librarian of Congress may establish, without regard to the second sentence of subsection (a) of this section, not more than 8 scientific or professional positions to carry out the research and development functions of the Library of Congress which require the services of specially qualified personnel.