Absorption of electromagnetic radiation by pure water vapor at frequencies near 1.5 THz

The water vapor self-continuum in the “terahertz gap” region (15–700 cm−1): Experiment versus MT_CKD-3.5 model

“…The MT_CKD-3.5 model was updated [3] considering laboratory experimental data on the continuum cross-section and its temperature dependence in the range of the pure rotational band of the water molecule (3.5-1100 cm -1 ) from our studies [4] (in the range of 70-700 cm -1 ), as well as from [5] (4.7-14.7 cm -1 ), [6] (3.5-5 cm -1 ), [7] (700-1100 cm -1 ), and [8] (333-633 cm -1 ). The MT_CKD-3.5 model reproduces the available experimental data [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] much better than its previous versions. At room temperature (296 K), the model on average follows experimental data almost in the whole range of the pure rotational band of the water molecule except for the range of 20-50 cm -1 , where the spectral feature related to rotational band of the stable dimer is observed (Figs.…”

“…Self-continuum temperature exponent: grey empty circles (SOLEIL measurements) [4], black triangles [7,11], grey squares [12], black star: [13], grey empty squares [16], black circles [15], black inverted triangles [5], red solid curve (continuum model obtained as a sum of true bound metastable dimers, and far-wings contributions simulated by in [1]), green dash curve (stable dimer) [19], orange solid curve (metastable dimer model), blue dash-dot curve (far wings model), green curve (MT_CKD-3.2 model) [2], and black solid curve (MT_CKD-3.5 model) [2]. [9,10], black empty triangles [11], grey squares [12], grey curve [18], grey empty squares [16], grey filled circles [15], grey star [17], green dash curve (stable dimer model), orange solid curve (metastable dimer model), blue dash-dot curve (far wings), red solid curve (continuum model obtained as a sum of true bound metastable dimers, and far-wings contributions simulated by in [1]), green curve (MT_CKD-3.2 model) [2], and black thin curve (MT_CKD-3.5 model).…”

“…Fig.1(analogue of Fig.1of Paper I). Self-continuum at 296 K: red circles (SOLEIL measurements)[4,9,10], green triangles[7,11], blue squares[12], black star[13], green empty triangles (measurements of R.A. Bohlander)[7], light green square[14], violet circles[15], orange empty squares[16], orange star[17], grey curve[18], green curve (MT_CKD-3.2 model)[2], and dashed and solid black curves are the MT_CKD-3.5 model[2] with and without "the pedestal" (see the text for details), respectively.…”

“…3 (analogue of Fig.4 of Paper I). Continuum spectral function: grey empty circles(SOLEIL measurements)[9,10], black empty triangles[11], grey squares[12], grey curve[18], grey empty squares[16], grey filled circles[15], grey star[17], green dash curve (stable dimer model), orange solid curve (metastable dimer model), blue dash-dot curve (far wings), red solid curve (continuum model obtained as a sum of true bound metastable dimers, and far-wings contributions simulated by in[1]), green curve (MT_CKD-3.2 model)[2], and black thin curve (MT_CKD-3.5 model).…”