Observation of singlet--triplet anticrossings in $sup 4$He$sub 2$

Journal Article · Sat Nov 01 04:00:00 EST 1975 · J. Chem. Phys., v. 63, no. 9, pp. 4042-4046

OSTI ID:4122685

Miller, T A; Freund, R S; Zegarski, B R; Jost, R; Lombardi, M; Derouard, J

Anticrossings between excited singlet and triplet levels of the He$sub 2$ molecule have been observed. Measurements have been made on anticrossings which take place between the f(3d)$sup 3$$delta$/sub u/ and F(3d)$sup 1$$delta$/ sub u/ states in both the v=0, N=2,3,4 and v=1, N=2 vibrational and rotational levels. Analysis of these results yields a new and more precise value for the excitation energy, T$sub 0$, from the a(2s)$sup 3$$Sigma$ to the A(2s)$sup 1$$Sigma$ state. This result, when combined with available optical data, fixes the absolute energy of all He$sub 2$ excited states. The present experiment establishes that the steady state populations of the $sup 3$$delta$ levels are greater than the $sup 1$$delta$ levels under a variety of excitation conditions. Also, collisional transfer may take place before radiation, giving rise to a given anticrossing signal appearing on optical emission lines of several nearby rotational levels. (AIP)

• Research Organization: Bell Laboratories, Murray Hill, New Jersey 07974
• NSA Number: NSA-33-010270
• OSTI ID: 4122685
• Journal Information: J. Chem. Phys., v. 63, no. 9, pp. 4042-4046, Journal Name: J. Chem. Phys., v. 63, no. 9, pp. 4042-4046; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

*HELIUM 4-- EXCITED STATES
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ENERGY LEVELS
ENERGY TRANSFER
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MOLECULES
N60200* --Physics (Atomic & Molecular)--Atomic & Molecular Properties
ROTATIONAL STATES
VIBRATIONAL STATES