Heaviside Operational Method for Delta Function Sequences

Delta function sequences are regular functions approaching the singular delta function. They represent more realistic physical models for concentrated sources than the idealized delta function. It is shown that delta function sequences can be formed in a straightforward manner through the Heaviside operational calculus, by defining quasi-differential broadening operators and operating on the singular delta function. Different operators and corresponding delta sequences are studied in one and three dimensions. Operator approach for removing the singularity of the Green function is considered as an application.