Helium atom, energy level diagram

Of greater interest in chemistry are lasers in which the active medium is a gas. The most common and least expensive gas laser is the helium-neon laser, which uses a mixture of 85% He and 15% Ne at pressures of the order of 10 torr. An energy-level diagram is shown in Fig. 14.14. An electric discharge excites He atoms to their H 25- S and S states, 19.8and20.6eV above the ground state. This energy... 

Like H atoms. He atoms have their electrons in Is orbitals, so we can construct an energy level diagram for He2 in a similar way. But there is one big difference each helium atom has two electrons so now both the bonding MO and the antibonding MO are full Any bonding due to the electrons in the bonding orbital is cancelled out by the electrons in the antibonding orbital, and the He2 molecule falls apart. He2 does not exist. 

Discuss the energy-level diagram and the spectrum of the helium atom. Which types of emission lines are seen in the spectrum The calcium atom... 

The KS orbital energy level diagram of the helium atom is shown in Figure 8. The zero is set at the onset of the continuum and is marked with a... 

Figure 8 Singlet energy level diagram for the helium atom. The Rydberg series of transition frequencies clustered below the ionization threshold can be seen. The frequencies cluster together, making it difficult to assess the quality of the TDDFT calculated spectra. As discussed in the text, the quantum defect is preferable for this purpose.

If the translational energies of the helium atoms are represented on an energy-level diagram, to account for the phenomena shown by Hell there must be a gap in the energy-level spectrum between the lowest level and the next, above which the spectrum of levels... 

Fig.11.7. Energy-level diagram for Cd showing known laser transitions pumped either by Penning ionization collisions with metastable helium atoms, He(2 S,),...

---