Electrical and Computer Engineering ETDs

Publication Date



An investigation is made of the classical force terms necessary to model adequately the structure and interatomic forces of the phosphate molecule. The two principal considerations chosen for use in judging the performance of models were:

1. Agreement with empirical spectral data on normal mode vibrational frequencies

2. Agreement with other known physical characteristics of the phosphate molecule

The performance of all models was good. Agreement with normal mode frequencies and phosphorus-oxygen bond lengths ranged from an RMS error of 5.4% in Model one to an RMS error of 1.5% in Model Five. An examination was made of six different models utilizing the following force terms:

1. Model One; Hooke's Law and Coulomb potential

2. Model Two; Hooke’s Law, Coulomb potential and angular valence

3. Model Three; Hooke's Law, Coulomb potential, angular valence and permanent dipole

4. Model Four; Hooke's Law, Coulomb potential and permanent dipole

5. Model Five; Hooke's Law, Coulomb potential, angular valence and induced dipole

6. Model Six; Hooke's Law, Coulomb potential and induced dipole

Although most complex, the model with the best overall performance was Model Five.

Document Type




Degree Name

Electrical Engineering

Level of Degree


Department Name

Electrical and Computer Engineering

First Committee Member (Chair)

Charles Leroy Beckel

Second Committee Member

Joseph Thomas Cordaro Jr

Third Committee Member

William Jackson Byatt

Fourth Committee Member

Merle John Benson