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.