The Tepper-García function, named after German-Mexican Astrophysicist Thor Tepper-García, is a combination of an exponential function and rational functions that approximates the line broadening function  over a wide range of its parameters.
It is obtained from a truncated power series expansion of the exact line broadening function.
In its most computationally efficient form, the Tepper-García function can be expressed as
where , , and .
Thus the line broadening function can be viewed, to first order, as a pure Gaussian function plus a correction factor that depends linearly on the microscopic properties of the absorbing medium (encoded in ); however, as a result of the early truncation in the series expansion, the error in the approximation is still of order , i.e. . This approximation has a relative accuracy of
over the full wavelength range of , provided that .
In addition to its high accuracy, the function  is easy to implement as well as computationally fast. It is widely used in the field of quasar absorption line analysis.