Photoionization and electron-ion recombination of Cr I Export

@article{citeulike:4582310, abstract = {Using the unified method, the inverse processes of photoionization and electron-ion recombination are studied in detail for neutral chromium, (Cr I + hν ↔ Cr II + e), for the ground and excited states. The unified method based on close-coupling approximation and R-matrix method (i) subsumes both the radiative recombination (RR) and dielectronic recombination (DR) for the total rate and (ii) provides self-consistent sets of photoionization cross sections σPI and recombination rates αRC. The present results show in total photoionization of the ground and excited states an enhancement in the background at the first excited threshold, 3d 4 4s 5 D state of the core. One prominent PEC (phot-excitation-of-core) resonance due to one dipole allowed transition ( 6 S– 6 P°) in the core is found in the photoionization cross sections of most of the valence electron excited states. Structures in the total and partial photoionization, for ionization in to various excited core states and ground state only respectively, are demonstrated. Results are presented for the septet and quintet states with n ≤ 10 and l ≤ 9 of Cr I. These states couple to the core ground state 6 S and contribute to the recombination rates. State-specific recombination rates are also presented for these states and their features are illustrated. The total recombination rate shows two DR peaks, one at a relatively low temperature, at 630 K, and the other around 40,000 K. This can explain existence of neutral Cr in interstellar medium. Calculations were carried out in LS coupling using a close-coupling wave function expansion of 40 core states. The results illustrate the features in the radiative processes of Cr I and provide photoionization cross sections and recombination rates with good approximation for this astrophysically important ion.}, author = {Nahar, Sultana N.}, citeulike-article-id = {4582310}, citeulike-linkout-0 = {http://dx.doi.org/10.1016/j.jqsrt.2009.04.015}, citeulike-linkout-1 = {http://linkinghub.elsevier.com/retrieve/pii/S0022407309001678}, day = {14}, doi = {10.1016/j.jqsrt.2009.04.015}, issn = {00224073}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, keywords = {photoionization, recombination}, month = {May}, posted-at = {2009-05-22 05:36:55}, priority = {2}, title = {Photoionization and electron-ion recombination of Cr I}, url = {http://dx.doi.org/10.1016/j.jqsrt.2009.04.015}, year = {2009} }

TY - JOUR ID - citeulike:4582310 L3 - citeulike-article-id:4582310 N2 - Using the unified method, the inverse processes of photoionization and electron-ion recombination are studied in detail for neutral chromium, (Cr I + hν ↔ Cr II + e), for the ground and excited states. The unified method based on close-coupling approximation and R-matrix method (i) subsumes both the radiative recombination (RR) and dielectronic recombination (DR) for the total rate and (ii) provides self-consistent sets of photoionization cross sections σPI and recombination rates αRC. The present results show in total photoionization of the ground and excited states an enhancement in the background at the first excited threshold, 3d 4 4s 5 D state of the core. One prominent PEC (phot-excitation-of-core) resonance due to one dipole allowed transition ( 6 S– 6 P°) in the core is found in the photoionization cross sections of most of the valence electron excited states. Structures in the total and partial photoionization, for ionization in to various excited core states and ground state only respectively, are demonstrated. Results are presented for the septet and quintet states with n ≤ 10 and l ≤ 9 of Cr I. These states couple to the core ground state 6 S and contribute to the recombination rates. State-specific recombination rates are also presented for these states and their features are illustrated. The total recombination rate shows two DR peaks, one at a relatively low temperature, at 630 K, and the other around 40,000 K. This can explain existence of neutral Cr in interstellar medium. Calculations were carried out in LS coupling using a close-coupling wave function expansion of 40 core states. The results illustrate the features in the radiative processes of Cr I and provide photoionization cross sections and recombination rates with good approximation for this astrophysically important ion. JF - Journal of Quantitative Spectroscopy and Radiative Transfer SN - 00224073 TI - Photoionization and electron-ion recombination of Cr I KW - photoionization KW - recombination AU - Nahar, Sultana PY - 2009/05/14/ UR - http://dx.doi.org/10.1016/j.jqsrt.2009.04.015 ER -