In—Cavity Laser Raman Spectroscopy of Vapors at Elevated Temperatures. As4 and As4O6

Abstract

The 632.8-nm radiation inside the cavity of an He–Ne laser is used to excite vibrational Raman spectra of As4 vapor at ∼ 610°C and As4O6 vapor at ∼ 440°C. As4 peaks are observed and assigned as follows: v1(a1), 344 cm−1; v2(e), 210 cm−1; and v3(f2), 255 cm−1. As4O6 vapor peaks are seen at 185, 253, 381, 409, 496, and 555 cm−1. An outside-cavity room-temperature spectrum of powdered As4O6 shows bands at 85, 189, 269, 371, 470, 560, and 782 cm−1. At a sample temperature of −178°C, the 85-cm−1 peak shifts to higher frequency by 4.4 cm−1. The molecular f2 fundamentals of As4O6 vapor are reassigned at 253, 346, 496, and 782 cm−1 based upon the disappearance of the 85-cm−1 low-frequency band upon going from solid to vapor, the temperature dependence of the 85-cm−1 band of the solid, comparison with assignments for P4O6, and comparison of computed absolute entropies of As4O6 vapor with entropies obtained from vapor pressure measurements, as well as literature single-crystal polarization measurements and infrared absorptions.

Density-functional study of small and medium-sizedAsnclusters up ton=28

“…[9][10][11][12][13][14][15][16][17][18][19] Dissociation energies of anionic As n were determined from appearance potentials and translational energies of the As − , As 2− , and As 3− ions formed by electron-impact induced dissociation of As 4 . 9 Raman spectroscopy was employed to study the vibrational modes of As 4 .…”

“…9 Raman spectroscopy was employed to study the vibrational modes of As 4 . 11,12 The electronic structure of the cationic and anionic clusters was investigated using photoelectron spectroscopy, [13][14][15][16][17] whereas the ionization potentials of the neutral As n were determined through photoionization mass spectrometry 18 and gas-phase charge-transfer reactions. 19 Most theoretical studies also considered small As n clusters ͑n ഛ 6͒.…”

First-Principles Studies on the Structural and Electronic Properties of As Clusters

“…Arsenic has been widely applied in many fields such as semiconductors, optoelectronics, and biopharmaceutics [2,3,4,5,6,7,8,9,10,11]. Besides, vanadium doped phosphorus clusters, and pure and doped arsenic clusters have received a large amount of attention from both experimental and theoretical fields in recent years [12,13,14,15,16,17,18,19,20,21,22,23]. …”

“…Experimentally, the study of As n clusters has focused on small-sized clusters with n ≤ 5 [12,13,14,15,16,17]. For example, Wang et al [12] utilized high-resolution photoelectron spectroscopy to study the electronic vibration and spin orbit of As 4 .…”

“…Lippa et al [14] have probed the electron affinities of As n ( n = 1–5) using photoelectron spectra in 1998. Brumbach and Rosenblatt [15] have investigated the vibrational modes of As 4 with Raman spectroscopy. Yonezo [16] designed a high-temperature nozzle assembly for gas-electron diffraction to determine the structure of As 4 .…”