#### Pregled bibliografske jedinice broj: 972408

## High Temperature Optical Spectra of Diatomic Molecules at Local Thermodynamic Equilibrium

High Temperature Optical Spectra of Diatomic Molecules at Local Thermodynamic Equilibrium

*// Atoms,*

**6**(2018), 4; 67, 20 doi:10.3390/atoms6040067 (međunarodna recenzija, članak, znanstveni)

**Naslov**

High Temperature Optical Spectra of Diatomic Molecules at Local Thermodynamic Equilibrium

**Autori**

Beuc, Robert ; Movre, Mladen ; Pichler, Goran

**Izvornik**

Atoms (2218-2004) **6**
(2018), 4;
67, 20

**Vrsta, podvrsta i kategorija rada**

Radovi u časopisima, članak, znanstveni

**Ključne riječi**

Diatomic molecules ; optical spectra ; thermodynamic equilibrium ; quantum-mechanical calculation ; semi-classical approximation

**Sažetak**

In the paper, several theoretical approaches to the determination of the reduced absorption and emission coefficients under local thermodynamic equilibrium conditions were exposed and discussed. The full quantum-mechanical procedure based on the Fourier grid Hamiltonian method was numerically robust but time consuming. In that method, all transitions between the bound, free, and quasi-bound states were treated as bound–bound transitions. The semi-classical method assumed continuous energies of ro-vibrational states, so it did not give the ro-vibrational structure of the molecular bands. That approach neglected the effects of turning points but agreed with the averaged-out quantum-mechanical spectra and it was computer time efficient. In the semi- quantum approximation, summing over the rotational quantum number J was done analytically using the classical Franck–Condon principle and the stationary–phase approximation and its consumption of computer time was lower by a few orders of magnitude than the case of the full quantum-mechanical approach. The approximation described well the vibrational but not the rotational structure of the molecular bands. All the above methods were compared and discussed in the case of a visible and near infrared spectrum of LiHe, Li2, and Cs2 molecules in the high temperature range.

**Izvorni jezik**

Engleski

**Znanstvena područja**

Fizika

**POVEZANOST RADA**

**Ustanove**

Institut za fiziku, Zagreb

**Autor s matičnim brojem:**

Goran Pichler, (37152)

Mladen Movre, (32514)

Robert Beuc, (50992)

#### Časopis indeksira:

- Web of Science Core Collection (WoSCC)
- Emerging Sources Citation Index (ESCI)
- Scopus