Fourier transforms occur in a variety of chemical systems and processes. A
few examples include obtaining spectral information from correlation functi
ons, energy relaxation processes, spectral densities obtained from force au
tocorrelation functions, etc. In this article, a new functional transform,
named the dual propagation inversion (DPI) is introduced. The DPI Functiona
l transform can be applied to a variety of problems in chemistry. such as F
ourier transforms of time correlation functions. energy relaxation processe
s, rate theory. etc, The present illustrative application is to generating
the frequency representation of a discrete, truncated time-domain signal. T
he DPI result is compared with the traditional Fourier transform applied to
the same truncated time signal. For both noise-free and noise-corrupted ti
me-truncated signals, the DPI spectrum is found to be more accurate. partic
ularly as the signal is more severely truncated. In the DPI, the distribute
d-approximating-functional free propagator is used to propagate and denoise
the signal simultaneously.