Emission Spectroscopy of AlH: the X¹Σ⁺, A¹Π and C¹Σ⁺ States Characteristics

Abstract

The visible spectrum of AlH has been investigated at high resolution between 20000 and 21500 cm −1 using a conventional spectroscopic technique. The AlH molecules were formed and excited in an aluminium hollow-cathode lamp with two anodes, filled with a mixture of Ne carried gas and a trace of NH 3 . The emission from the discharge was observed with a plane grating spectrograph and recorded by a photomultiplier tube. The 0-0 and 1-1 bands of the C

Ab Initio Ground‐State Potential Energy Function and Vibration‐Rotation Energy Levels of Aluminum Monohydride

“…The large discrepancy between the two experimental estimates of r e is quite puzzling at first glance. It results from distinctly different ways of deriving the equilibrium distance r e in both the experimental studies . The later value still includes mass‐dependent contributions resulting from the adiabatic and nonadiabatic effects.…”

“…The predicted equilibrium distance r e is in perfect agreement with the experimental Born-Oppenheimer estimate of 1.6453622(21) Å by White et al [12] However, given the (conservative) uncertainty in the ab initio predicted r e value due to the limited basis set size, such quantitative agreement seems to be somewhat fortuitous. An another experimental estimate of the equilibrium distance r e of AlH in its X 1 Σ + state was reported by Szajna et al [22] to be 1.64735188(26) Å. The large discrepancy between the two experimental estimates of r e is quite puzzling at first glance.…”

“…An another experimental estimate of the equilibrium distance r e of AlH in its X 1 ∑ + state was reported by Szajna et al . to be 1.64735188(26) å. The large discrepancy between the two experimental estimates of r e is quite puzzling at first glance.…”

“…[12] The vibration-rotation spectra of AlH and AlD attracted also significant interest by various experimentalists, see Refs. [12][13][14][15][16][17][18][19][20][21][22][23][24][25] and references therein. The vibration-rotation energy levels of the X 1 Σ + state of AlH and AlD were characterized by high-resolution spectroscopy up to the seventh excited vibrational state.…”

Photodissociation and photoionisation of atoms and molecules of astrophysical interest

“…Vertical transitions calculated from this data at the equilibrium geometry give absorption at 430 and 230 nm with oscillator strengths of 0.0022 and 0.090, respectively. This however represents an upper limit for photodissociation because unbroadened emission lines from the v = 0 and 1 levels of both the A and C states is observed (Szajna & Zachwieja 2010;Szajna et al 2011). The predissociation of higher energy vibrational structure for both states may be possible however if they are able to tunnel through maxima predicted for both potential-energy curves (Matos et al 1987;Bauschlicher & Langhoff 1988).…”