Here, he aimed to rationalize the shapes adopted by polyatomic molecules in the ground state as well as in excited states, by applying theoretical contributions made by Mulliken.
12.
For a diatomic molecule like CO or HCl or a linear polyatomic molecule like OCS in its ground vibrational state, the allowed rotational energies in the rigid rotor approximation are
13.
The normal modes of vibration of polyatomic molecules are independent of each other but each normal mode will involve simultaneous vibrations of different parts of the molecule such as different chemical bonds.
14.
In polyatomic molecules, other rotational modes may become active, due to the much higher moments of inertia about certain axes which do not coincide with the linear axis of a linear molecule.
15.
Thus, the effect of higher temperatures and vibrational heat capacity acts to increase the difference between the speed of sound in monatomic vs . polyatomic molecules, with the speed remaining greater in monatomics.
16.
For simple polyatomic molecules with a " central atom " such as methane ( ) or carbon dioxide ( ), a MO diagram may show one of the identical bonds to the central atom.
17.
In the late 1940s, Herzfeld increased the attention at Catholic University to quantum-mechanical calculations on the electronic structure of polyatomic molecules, thus establishing a respected position for the University in this field.
18.
Recent research ( including ongoing ) addresses issues in amorphous solid water, photophysics in doped superfluid helium nanodroplets, complex photochemistry and photophysics of polyatomic molecules, and theories of particle statistics and geometric phases.
19.
He also noted that Mulliken had previously attempted to construct a correlation diagram for the possible orbitals of a polyatomic molecule in two different nuclear configurations, and had even tried to use this diagram to explain shapes and spectra of molecules in their ground and excited states.
20.
While the structure of diatomic, triatomic or tetra atomic molecules may be trivial, ( linear, angular pyramidal etc . ) the structure of polyatomic molecules, that are constituted of more than six atoms ( of several elements ) can be crucial for its chemical nature.
