Question

Is the function being called correctly?

format shorteng

r = linspace(0.1,4,500); % Distance in Angstrom
re = 0.7414; % Equilibrium Seperation
D = 38292; % Dissoc Enrgey [cm^-1]
twoBeta = 1.4426;

Vm = morse_potential(D, twoBeta, re, r); % Call Morse Potential Function

plot(r,Vm, 'g-','Linewidth',2)
xlabel('Distance [A]')
ylabel('Potential Energy [cm^-1]')
title('Morse Potential of Hydrogens')
ylim([0,5e4])
grid 'on'
hold on

D2 = 38292; % Equiibrium distance
re2 = 0.7413; % Width of the potential well for H2
twoBeta2 = 1.4433;
r = linspace(0.4,4,500); % Seperation distances

Vm2 = morse_potential(D2, twoBeta2, re2, r);
plot(r,Vm)
hold on

D3 = 38292; % Equiibrium distance
re3 = 0.7417; % Width of the potential well for H2
twoBeta3 = 1.4446;
r = linspace(0,4,500); % Seperation distances
Vm3 = morse_potential(D3, twoBeta3, re3, r);
plot(r,Vm,'r--', 'Linewidth', 1)

x1 = [0.29,4];
y1 = [3.82e4,3.82e4];
plot(x1,y1,':r','linewidth', 2)

legend('Hydrogen','Hydrogen Deuteride','Deuterium','DissEnergy')
hold off

%% Metal Hydrides
figure(2)
format SHORTENG
r = linspace(0.1,4,500); % Distance in Angstrom
re = 1.5947; % Equilibrium Seperation
D = 7660; % Dissoc Enrgey [cm^-1]
twoBeta = 3.5536;

Vm = morse_potential(D, twoBeta, re, r); % Call Morse Potential Function

plot(r,Vm, 'g-','Linewidth',2)
xlabel('Distance [A]')
ylabel('Potential Energy [cm^-1]')
title('Potential of Metal Hydrides')
ylim([0,1e4])
grid 'on'
hold on

D2 = 6184; % Equiibrium distance
re2 = 1.762; % Width of the potential well
twoBeta2 = 3.901;
r = linspace(0.1,4,500); % Seperation distances

Vm2 = morse_potential(D2, twoBeta2, re2, r);
plot(r,Vm2, 'b-','Linewidth',2)
hold on

D3 = 3695; % Equiibrium distance
re3 = 1.741; % Width of the potential well for H2
twoBeta3 = 4.844;
r = linspace(0,4,500); % Seperation distances
Vm3 = morse_potential(D3, twoBeta3, re3, r);
plot(r,Vm3,'r--', 'Linewidth', 1.5)
hold on
x1 = [1.3,4];
y1 = [7.65e3,7.65e3];
plot(x1,y1,':r','linewidth', 2)
x2 = [1.46,4];
y2 = [6.1e3,6.1e3];
plot(x2,y2,':r','linewidth', 2)
x3 = [1.5,4];
y3 = [3.7e3,3.7e3];
plot(x3,y3,':r','linewidth', 2)
legend('Zinc Hydride','Cadium Hydride','Mercury Hydride','DissEnergy')
hold off

function [Vm] = morse_potential(D,twoBeta, re, r)
%-----------------------------------------------------------------------
% Function Description: Computes the Morse Potential for a diatomic
% molecule
% ---Inputs---
% Input1: D - Energy required to break the moclecuar bond
% Input2: twoBeta - Morse potential parameter [Controls width of well]
% Input3: re - Equilibrium seperatin distance
% Input4: r - Seperation distance
% ---Outputs---
% Output1: Vm - Potential energy as a function of seperation distance

%% Morse Potential
% Compute xi
xi = (r - re)./re;
%[R, Re] = meshgrid(r,re);
%xi = (R - Re)./Re;
% Compute x
x = twoBeta.* xi;

% Compute Vm
Vm = D'.*(1-exp(-x)).^2;

am i calling the morse_potential function correctly? the code is not consistent from hyrogens to metal hydrides

Answer 1

Vm2 and Vm3, are not getting plotted, you were plotting Vm only three times

format shorteng;

r = linspace(0.1,4,500); % Distance in Angstrom
re = 0.7414; % Equilibrium Seperation
D = 38292; % Dissoc Enrgey [cm^-1]
twoBeta = 1.4426;

Vm = morse_potential(D, twoBeta, re, r); % Call Morse Potential Function

figure(1);
plot(r,Vm, 'g-','Linewidth',2)
xlabel('Distance [A]')
ylabel('Potential Energy [cm^-1]')
title('Morse Potential of Hydrogens')
ylim([0,5e4])
grid 'on'
hold on

D2 = 38292; % Equiibrium distance
re2 = 0.7413; % Width of the potential well for H2
twoBeta2 = 1.4433;
r = linspace(0.4,4,500); % Seperation distances

Vm2 = morse_potential(D2, twoBeta2, re2, r);
plot(r,Vm2)
hold on

D3 = 38292; % Equiibrium distance
re3 = 0.7417; % Width of the potential well for H2
twoBeta3 = 1.4446;
r = linspace(0,4,500); % Seperation distances
Vm3 = morse_potential(D3, twoBeta3, re3, r);
plot(r,Vm3,'r--', 'Linewidth', 1)

x1 = [0.29,4];
y1 = [3.82e4,3.82e4];
plot(x1,y1,':r','linewidth', 2)

legend('Hydrogen','Hydrogen Deuteride','Deuterium','DissEnergy')
hold off

%% Metal Hydrides
figure(2)
format SHORTENG
r = linspace(0.1,4,500); % Distance in Angstrom
re = 1.5947; % Equilibrium Seperation
D = 7660; % Dissoc Enrgey [cm^-1]
twoBeta = 3.5536;

Vm = morse_potential(D, twoBeta, re, r); % Call Morse Potential Function

plot(r,Vm, 'g-','Linewidth',2)
xlabel('Distance [A]')
ylabel('Potential Energy [cm^-1]')
title('Potential of Metal Hydrides')
ylim([0,1e4])
grid 'on'
hold on

D2 = 6184; % Equiibrium distance
re2 = 1.762; % Width of the potential well
twoBeta2 = 3.901;
r = linspace(0.1,4,500); % Seperation distances

Vm2 = morse_potential(D2, twoBeta2, re2, r);
plot(r,Vm2, 'b-','Linewidth',2)
hold on

D3 = 3695; % Equiibrium distance
re3 = 1.741; % Width of the potential well for H2
twoBeta3 = 4.844;
r = linspace(0,4,500); % Seperation distances
Vm3 = morse_potential(D3, twoBeta3, re3, r);
plot(r,Vm3,'r--', 'Linewidth', 1.5)
hold on
x1 = [1.3,4];
y1 = [7.65e3,7.65e3];
plot(x1,y1,':r','linewidth', 2)
x2 = [1.46,4];
y2 = [6.1e3,6.1e3];
plot(x2,y2,':r','linewidth', 2)
x3 = [1.5,4];
y3 = [3.7e3,3.7e3];
plot(x3,y3,':r','linewidth', 2)
legend('Zinc Hydride','Cadium Hydride','Mercury Hydride','DissEnergy')
hold off

function [Vm] = morse_potential(D,twoBeta, re, r)
%-----------------------------------------------------------------------
% Function Description: Computes the Morse Potential for a diatomic
% molecule
% ---Inputs---
% Input1: D - Energy required to break the moclecuar bond
% Input2: twoBeta - Morse potential parameter [Controls width of well]
% Input3: re - Equilibrium seperatin distance
% Input4: r - Seperation distance
% ---Outputs---
% Output1: Vm - Potential energy as a function of seperation distance

%% Morse Potential
% Compute xi
xi = (r - re)./re;
%[R, Re] = meshgrid(r,re);
%xi = (R - Re)./Re;
% Compute x
x = twoBeta.* xi;

% Compute Vm
Vm = D'.*(1-exp(-x)).^2;
end