Search

Electronic transition spectrum of cobalt monoboride (CoB) in the visible region between 495 and 560 nm has been observed and analyzed using laser-induced fluorescence spectroscopy. CoB molecule was produced by the reaction of laser-ablated cobalt atom and diborane (B2H6) seeded in argon. Fifteen vibrational bands with resolved rotational structure have been recorded, which included transitions of both Co10B and Co11B isotopic species. Our analysis showed that the observed transition bands are ΔΩ = 0 transitions with Ω″ = 2 and Ω″ = 3 lower states. Four transition systems have been assigned, namely, the [18.1]3Π2-X3Δ2, the [18.3]3[uppercase_phi_synonym]3-X3Δ3, the [18.6]3- X3Δ3, and the [19.0]2-X3Δ2 systems. The bond length, ro, of the X 3Δ3 state of CoB is determined to be 1.705 Å. The observed rotational lines showed unresolved hyperfine structure arising from the nuclei, which conforms to the Hund's case (aβ) coupling scheme. This work represents the first experimental investigation of the CoB spectrum. [ABSTRACT FROM AUTHOR]

High resolution laser induced fluorescence spectrum of IrB in the spectral region between 545 and 610 nm has been recorded and analyzed. Reacting laser-ablated iridium atoms with 1% B2H6 seeded in argon produced the IrB molecule. This is the first experimental observation of the IrB molecule. Four vibronic transition bands, (v,0) with v=0–3 of an electronic transition system, have been observed. Spectra of all four isotopic molecules, 191Ir10B, 193Ir10B, 191Ir11B, and 193Ir11B, were recorded. Isotopic relationships confirmed the carrier of the spectra and the vibrational quantum number assignment. Preliminary analysis of rotational lines showed that these vibronic bands are with Ω′=2 and Ω″=3. The electronic transition identified is assigned as the [16.5]3Π2-X 3Δ3 system. Partially resolved hyperfine structure which conforms to the Hund’s case aβ coupling scheme has been observed and analyzed. The bond length r0 of the lower X 3Δ3 state of IrB was determined to be 1.7675 Å. [ABSTRACT FROM AUTHOR]

Laser induced fluorescence spectrum of NiBr in the visible region between 604 and 666 nm has been recorded and analyzed. Fourteen bands belonging to three electronic transition systems, namely, [15.1] 2Δ5/2–X 2Π3/2, [15.1] 2Π3/2–X 2Π3/2, and [14.0] 2Δ5/2–X 2Π3/2 have been observed. Spectra of isotopic molecules were also observed and analyzed. Detailed analysis of the recorded spectra indicated that the two electronic states [15.1] 2Π3/2 and [15.1] 2Δ5/2 lie about 1 cm-1 apart from each other and J-dependent perturbation due to spin-uncoupling interaction has been observed. Least squares fitting procedures involving deperturbation matrix elements were used to fit the observed line positions, which yielded accurate molecular constants for the [15.1] 2Π3/2 and [15.1] 2Δ5/2 states. In addition, the (1,0) band of the [15.1] 2Δ5/2–X 2Π3/2 transition shows partially resolved hyperfine structure that was caused by the interaction of unpaired electron with the magnetic moment of the Br nucleus (nuclear spin of I=3/2) in the excited state. The rapid decrease in hyperfine width as J increases suggests that the hyperfine coupling in the excited state conforms to Hund’s case (aβ) coupling scheme. [ABSTRACT FROM AUTHOR]

Laser-induced fluorescence spectrum of NiI in the near infrared region of 714–770 nm has been recorded. Seven bands belonging to three electronic transition systems were observed and analyzed: the (0,0), (1,0), and (2,0) bands of [13.3] 2Σ+-A 2Π3/2 system; the (1,1) and (0,1) bands of [13.9] 2Π3/2-X 2Δ5/2 system; and the (0,0) and (1,0) bands of [13.9] 2Π3/2-A 2Π3/2 system. Spectra of isotopic molecules confirmed the vibrational quantum number assignment of the observed bands. Least-squares fit of rotationally resolved transition lines yielded accurate molecular constants for the v=0–2 levels of the [13.3] 2Σ+ state, the v=0 level of the A 2Π3/2, and the v=1 level of the X 2Δ5/2 state. The vibrational separation, ΔG1/2, of the ground state was measured to be 276.674 cm-1. With the observation of the [13.9] 2Π3/2-A 2Π3/2 and [13.9] 2Π3/2-X 2Δ5/2 transitions, we accurately determined the energy separation between the A 2Π3/2 and the X 2Δ5/2 to be 163.847 cm-1. This confirms that the order of the A 2Π3/2 and X 2Δ5/2 states in NiI is reversed when compared with other nickel monohalides. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

High-resolution laser-induced fluorescence spectrum of a jet-cooled NiI molecule has been recorded in the near infrared and visible regions. The NiI molecule was produced by reacting laser-ablated nickel atom and methyl iodide (CH[sub 3]I). Three electronic states have been identified that include the X [sup 2]Δ[sub 5/2] and two low-lying [13.9] [sup 2]Π[sub 3/2] and [14.6] [sup 2]Δ[sub 5/2] excited states. Molecular transition bands (v[sup ′],0) of the [13.9] [sup 2]Π[sub 3/2]-X [sup 2]Δ[sub 5/2] system with v[sup ′]=0, 4–9, and the (v[sup ′],0) bands of the [14.6] [sup 2]Δ[sub 5/2]-X [sup 2]Δ[sub 5/2] system with v[sup ′]=0–6 were observed and analyzed. Spectra of isotopic molecules confirmed the assignment of vibrational quantum number of the observed bands. Least squares fit of rotational transition lines yielded accurate molecular constants for the states studied. The bond length r[sub 0] measured for the X [sup 2]Δ[sub 5/2] is 2.3479 Å and the equilibrium bond length, r[sub e], for the [13.9] [sup 2]Π[sub 3/2] and [14.6] [sup 2]Δ[sub 5/2] are, respectively, 2.4834 and 2.5081 Å. With the use of a molecular orbital energy level diagram, we have examined the electronic configurations that give rise to the X [sup 2]Π[sub 3/2] ground state for NiF, NiCl, and NiBr, but the X [sup 2]Δ[sub 5/2] state for NiI. This work represents the first spectroscopic study of the NiI molecule. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Electronic transitions of cobalt monochloride and cobalt monoiodide have been studied using laser vaporization-reaction free jet expansion and laser induced fluorescence spectroscopy in the near infrared region. The observed transitions have been identified as the [10.3] 3Φ[SUB4]-X 3Φ[SUB4] transition of CoCl and [11.0] 3Φ[SUB4]-X 3Φ[SUB4] transition of CoI. The magnetic hyperfine structure arising from the cobalt nucleus with I = 7/2 was resolved and analyzed. Accurate rotational and hyperfine parameters for the [10.3] 3Φ[SUB4] and X 3Φ[SUB4] states of CoCl and [11.0] 3Φ[SUB4] and X 3Φ[SUB4] states of CoI have been obtained. Comparison of Fermi contact parameters, b[SUBF], for the upper states indicated that the observed [10.3] 3Φ[SUB4]-X 3Φ[SUB4] transition of CoCl and [11.0] 3Φ[SUB4]-X 3Φ[SUB4] transition of CoI have arisen from the promotion of an electron from the bonding s orbital to a slightly antibonding σ orbital. Observed low-lying 3Φ states of the cobalt monohalides and hydride are also compared and discussed. [ABSTRACT FROM AUTHOR]

The electronic structures and spectroscopic parameters of the ground and some low-lying excited states of the first-row transition metal phosphides have been calculated with the density functional theory using the Becke three-parameter hybrid exchange functional with the Lee-Yang-Parr correlation functional (B3LYP). The ground states of the transition metal phosphides are found to be [SUP1]∑[SUP+] (ScP), [SUP2]Δ (TiP), [SUP3]Δ (VP), [SUP4]∑[SUP-] (CrP), [SUP5]Π (MnP), [SUP6]∑[SUP-] (FeP), [SUP5]Δ (CoP), [SUP4]Δ (NiP), and [SUP3]∑[SUP-] (CuP). The B3LYP functional predicts an increase in covalent character in the bonds between the metal and the phosphorus across the transition metal series. The energies of the low-lying excited states relative to the ground state for TiP, FeP, and CoP have been found to be so small that many low-lying states are possible candidates to be the ground state. [ABSTRACT FROM AUTHOR]