Nucleus – Isomers

The term isomer is taken from chemistry, where it refers to molecules that have different geometrical configurations of the same collections of atoms. There are different states to nuclear isomers, such as ground state and metastable state. A metastable state is produced through nuclear fusion and other nuclear reactions, and they are formed due to reactions such as the bombardment of nuclei. 

The excited state of the isomers has half-lives 100 to 1000 times longer than the half-lives of excited nuclear states. The term metastable is only used for isomers with half-lives of 10-9 seconds or longer. Other sources recommend 5×10-9s to distinguish the metastable half-life from the average prompt gamma emission half-life. In a nuclear isomer, the nucleus has a higher energy state than the other non-excited nucleus, which excites in the lower energy state called the ground state. 

Isomers

Nuclear isomers are defined as an atom whose nuclei exist in excited states for a measurable period of time. Isomeric nuclei are different states of the same numbers of protons and neutrons. In contrast, chemical isomers have energy states that are similar, sometimes identical, to each other. Nuclei isomers always have different energies. 

An example of a nuclear isomer is 99mTc, an excited state of Technetium-99. The “m” denotes a metastable state. i.e., is a long-lived isomer. By contrast, the typical half-lives of excited nuclear states are about a picosecond. These isomers live at least a thousand times longer. The subscript “m” is even more restrictive: it’s reserved for isomers with half-lives of more than a millisecond. If a nuclear species has more than one metastable isomer, the “m” distinguishes between them in ascending order of excitation energy.

Nuclear isomerism

Nuclear isomerism is caused due to the two lowest nuclear states with zero angular momentum and the opposite party. Their lifetime is estimated under these conditions of two quanta and for the ejection of two elections from the K or L shell. It is also exhibited by all diatomic molecules having an odd Z value.

Nucleus 

The nucleus is known as the centre of an atom where the positive charge and mass are densely concentrated, and more than 99.9% mass of the atom is concentrated in the nucleus. The atomic mass unit is defined as 1/12th of the mass of a carbon atom (C12). The composition of the nucleus is described by atomic number Z and Mass Number A. 

The nucleus of a nuclear isomer has a higher energy state than the other non-excited nucleus, which exists in the lowest energy state known as the ground state.

What are Isomers?

Isomers are atoms that consist of the same number of protons and the same number of neutrons but are different in energy and manner of radioactive decay and exist for a particular period of time. There are different states to nuclear isomers, such as ground state and metastable state. A metastable state is produced through nuclear fusion and other nuclear reactions. All diatomic molecules reveal isomers with an odd Z value, and nuclei with an odd Z value result in nuclear spin and exhibit nuclear isomerism.

Metastable isomers

They are produced through nuclear fusion or other nuclear reactions. The different kinds of Metastable isomers are the fission isomer or shape isomer. Metastable isomers are designated with an “m”, and it is placed after the mass number of the atom, for example, Cobalt-58m.

Ground state isomers

The excited nuclear states are unstable and radiate away from the extra energy after existing on the order of 10-12 seconds. One of the most stable nuclear isomers occurring in nature is 180m73Ta, present in the samples of Tantalum. 

Nuclear force

The force acting inside the nucleus is called nuclear force. The nuclear force is a non-central and non-conservative force and is an independent charge. Compared to the electrostatic force and gravitational force, it is 100 times the electrostatic force and 1038 times that of gravitational force. It is a force that acts between the protons and neutrons of an atom. Nuclear force plays a significant role in storing energy used in nuclear power and nuclear weapons.

Conclusion

In this article, we have discussed isomers and their different energy states. Isomers are atoms that consist of the same number of protons and the same number of neutrons but are different in energy and manner of radioactive decay and exist for a particular period of time. The nucleus of a nuclear isomer has a higher energy state than the other non-excited nucleus, which exists in the lowest energy state known as the ground state. So overall, we read about isomers, nucleus, nuclear force, and different energy states of isomers.