This subchapter applies to -
(a) Civilian officers and employees of -
(1) Executive departments as defined in 5 U.S.C. 101;
(2) Independent establishments as defined in 5 U.S.C. 104;
(3) Government corporations subject to chapter 91 of title 31 U.S.C.;
(4) The Library of Congress;
(5) The Government Printing Office (GPO);
(6) The government of the District of Columbia; and
(b) Commissioned officers of the National Oceanic and Atmospheric Administration.