CODATA recommended values of the fundamental physical constants: 1998

This paper gives the 1998 self-consistent set of values of the basic consta nts and conversion factors of physics and chemistry recommended by the Comm ittee on Data for Science and Technology (CODATA) for international use. Fu rther, it describes in detail the adjustment of the values of the subset of constants on which the complete 1998 set of recommended values is based. T he 1998 set replaces its immediate predecessor recommended by CODATA in 198 6. The new adjustment, which takes into account all of the data available t hrough 31 December 1998, is a significant advance over its 1986 counterpart . The standard uncertainties (i.e., estimated standard deviations) of the n ew recommended values are in most cases about 1/5 to 1/12 and in some cases 1/160 times the standard uncertainties of the corresponding 1986 values. M oreover, in almost all cases the absolute values of the differences between the 1998 values and the corresponding 1986 values are less than twice the standard uncertainties of the 1986 values. The new set of recommended value s is available on the World Wide Web at physics.nist.gov/constants.