H Martin

Laser Spectroscopic Investigations of CaCl

Laser excitation and fluorescence spectra of the A2Π–X2Σ transition of gaseous calcium chloride have been observed and analyzed. Traditional absorption spectra were also recorded in a high-resolution spectrograph. Totally 1949 rotational lines were used in the calculations and the following molecular equilibrium constants (cm-1) were determined by least squares methods. The numbers in parentheses represent one standard deviation in the last digit

Laser Spectroscopic Investigations of CaCl. II. Rotational Analysis of the B2Σ- X2 Σ Transitions

Diatomic calcium chloride has been examined by means of laser excitation and fluorescence spectroscopy. A small resistance furnace and a c.w. Rhodamine 6G dye laser were used to produce the spectra. The absorption spectrum of CaCl was also recorded by using a 5 m Jarrel Ash spectrograph. The following rotational and vibrational constants of the B2Σ and X2Σ states have been derived (cm-1): B2Σ+ X2Σ+ Te 16 856.684(4) 0.0 ωe 367.196(6) 370.201(1) ωexe 1.524(2) 1.3732(1) ωeye 8.6(2) × 10-3 9.3 × 10-3 ωeze -3.8(2) × 10-4 -4.8(2) × 10-4 Be 0.154 704(1) 0.152 233 αe 8.835(3) × 10-4 7.92 × 10-4 De 1.1409(4) × 10-7 1.068 × 10-7 γe -6.531(7) × 10-2 1.38 × 10-3 γD 1.36(6) × 10-7 0.0 αγ -4.0(6) × 10-4 0.0 The figures in parentheses stand for one standard deviation in the last digit for the computed quantity.

Polarization Effects in Gaseous Calcium Chloride

The Ca+(3d2D) polarizabilities are evaluated by fitting a model of a polarizable ion pair to the experimental results of the low lying electronic states in CaCl. The Ca+(2D) polarizabilities are found to be α = 5.10 A3, αΣ = 4.16 A3 and αΔ = 0.6 A3. From these new data the location of the so far unobserved 2Δ state in CaCl is estimated to Te = 21 000 cm-1. Molecular static dipole moments, induced dipole moments, electronic structures and transition moments are thus evaluated as a function of internuclear distance for CaCl and are found to well represent the behaviour of the other Ca-halides as well. Finally the lifetimes of the A, B and C states of the Ca-monohalides are derived.

On the Interaction Between the A2 Π and B2 Σ States of the CaCl Molecule

A deperturbation of the interaction between the A 2Π and B 2Σ states in CaCl is presented. The results are used to determine the mixing coefficients in a 4p, 3d, 4f Ca+ orbital hybridization model for the low lying electronic states in CaCl. These mixing coefficients are used in the interaction calculation to predict the equilibrium energy of the hitherto unobserved 2Δ molecular state. The mixing coefficients obtained are close to the ones predicted from the model of polarizable ions where the A and B states correlate to the Ca+ (2D) + Cl- (2S) states of the separated ions.

Observations of Two Photon Absorption in Gaseous CaCl. A Study of the D 2Σ and X 2Σ States

In the wavelength region, 616-623 nm, two photon processes have been observed in diatomic calcium chloride. The D 2Σ-X 2Σ transitions of both Ca35Cl and Ca37Cl were obtained. Rotational and vibrational constants have been derived for the D 2Σ and X 2Σ states of Ca35Cl.

A Study of the X2 Σ Potential Energy Curve of the Gaseous Calcium Chloride Molecule

Different models describing ionic potential energy curves have been fitted to a RKR potential derived from the twelve lowest vibrational levels of the X2 Σ+ state in CaCl. The effect of covalent influence in the bond was studied. It turns out that the dissociation energies as well as the polarizabilities of the singly charged ions are well determined from the observed Bv and Tv values.

Ionic Bonds in the Group IIA Hydrides

The electronic states of the group IIA diatomic hydrides and halides are discussed. There are obvious similarities between the optical spectra of hydrides and halides which are most conveniently explained by the ionic character of the halides. If ionic bonds also are considered in some of the hydride states, several recent observations fall naturally in place.

Rotational Analysis of the D2Σ-X2Σ Transition of CaCl

The absorption spectrum of gaseous CaCl in the wavelength region 2990-3300 A has been studied using a King furnace. Ten bands belonging to the D2Σ-X2Σ transition have been analyzed and both vibrational and rotational constants have been evaluated. The following molecular constants have been determined (cm-1): X2Σ D2Σ Te 0.0 31 110.934(5) ωe 370.201 423.254(7) ωexe 1.3732 1.581(3) ωeye 9.3 × 10-3 1.6(4) × 10-3 ωeze -4.8 × 10-4 -2.9(2) × 10-4 Be 0.152 233 0.162 975 4(8) αe 7.92 × 10-4 7.968(2) × 10-4 De 1.068 × 10-7 1.0090(3) × 10-7 γe 1.38 × 10-3 1.2 × 10-3 The figures in parentheses stand for one standard deviation in the last digit for the computed quantity.