#### Title

A Spherically Symmetric Potential for Ar*(3P2 ̣0)+O2 from Velocity Dependent Total Cross Sections

#### Document Type

Thesis

#### Degree

Master of Science (MS)

#### Major/Program

Physics

#### First Advisor's Name

Kenneth A. Hardy

#### First Advisor's Committee Title

Committee Chair

#### Second Advisor's Name

Yesim Darici

#### Third Advisor's Name

Jeffrey A. Joens

#### Fourth Advisor's Name

John W. Sheldon

#### Date of Defense

8-14-1989

#### Abstract

Velocity dependent total cross sections σ(g) were measured for Ar^{*} (^{3}P_{2,0})-O_{2} in the range covering 600-3000 ms^{-1} using a single beam technique. The measured cross sections σ(g) were determined from the attenuation of the statistically mixed (the ^{3}P_{2} dominates the ^{3}P_{0} state by a ratio of 5:1) Ar^{*} beam due its interaction with O_{2}, which was contained in a scattering cell. The absolute value and velocity dependence of σ(g) give information on the long range forces and well area of the potential. The parameters Σ and R_{m} (Σ is the well depth and R_{m} is the well position) were derived by a semiclassical inversion technique. These parameters were Σ = 9.73 x 10^{-5} au. and R_{m} = 8.60 au.

Using the parameters obtained from the semiclassical inversion technique as input, the measured cross sections were compared to those obtained from a numerical integration of the Schrodinger equation using an assumed potential of the form:

V(r) = (Σ[(f+5)/(n-5) (R_{m}/R)^{n} - [n(1-f)+6f]/(n-5) (R_{m}/R)^{5}

- f(R_{m}/R)^{6}]

The 1/R^{5} dependence in the potential is a measure of a quadrupole-quadrupole interaction. This dependence is believed to be present in the Ar^{*}-O_{2} system, as both Ar^{*} and O_{2} have quadrupole moments. The resulting potential parameters were (Σ = 9.24 10^{-5} au., n = 10, R_{m} = 9.00 au., and f = 1.27.

The ratio of the C_{5} terms (C_{5} = [n(1-f)+6f)/(n-5)]R_{M}^{5} For the Ar^{*}-O_{2} and Ar^{*}-N_{2} systems, which should be proportional to the ratio of their quadrupole moments for O_{2} and N_{2}, was computed. This ratio was found to be:

C_{5}(N_{2})/C_{5}(O_{2}) = 1.25

This ratio is of the same order of magnitude as the ratio of the quadrupole moments for O_{2} and N_{2}.

#### Identifier

FI15101588

#### Recommended Citation

Gillman, Edward, "A Spherically Symmetric Potential for Ar*(3P2 ̣0)+O2 from Velocity Dependent Total Cross Sections" (1989). *FIU Electronic Theses and Dissertations*. 3996.

https://digitalcommons.fiu.edu/etd/3996

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