# Accession Number:

## AD0254860

# Title:

## ATOMIC SCATTERING PROCESSES

# Descriptive Note:

# Corporate Author:

## PLESSET (E H) ASSOCIATES INC SANTA MONICA CA

# Personal Author(s):

# Report Date:

## 1961-01-30

# Pagination or Media Count:

## 1.0

# Abstract:

Understanding of atomic collision processes during the past three years or so are reviewed. Recent theoretical and experimental developments in the elastic scattering of electrons by atomic hydrogen are discussed, as well as theoretical and experimental developments in the collisions of heavy particles, i.e., atom-atomf process include apparent deviations from theoretical prediction. This apparent contradiction arises from the fact that in no actual collision problem are the theoretical equations solvable without approximation. In fact, atomic collision problems are mathematically so complicated that in the past it has not beeand ion-atom collisions. It is emphasized that there exist successful calculations for just about every type of collision process, but that on the other hand the data in every type of process include apparent deviations from theoretical prediction. This apparent contradiction arises from the fact that in no actual collision problem are the theoretical equations solvable without approximation. In fact, atomic collision problems are mathematically so complicated that in the past it has not been possible to place even crude limits of error on the approximations employed. Very recent theoretical advances, due mainly to Spruch and coworkers, may make it practical to estimate approximation errors, and therewith to decide how approximate wave functions should be modified in order to improve the accuracy of theoretical cross sections. It also is pointed out that very recent theoretical work suggests Born approximation may not be valid for rearrangement collisions at high energies, although this is a domain in which Born approximation has been and continues to be commonly employed. Author