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Rayleigh light scattering spectra in critical mixtures
73
JOUrn& Of i%fOkCUilXF LigUidS, Fi4 (1992) 78-76 Elsevier Science Publishers B-V.. Amsterdam
lIArnIGH
LICEIT
sm
ING
spBI=TRB
IN
CRrrICAL
-
LM:.Ka6haeva, V.Yk.a.Lermm, L.M.Sabirov. T.M.Utarova and Ya.!Pmakulov Sanmrkmnd State Univemity, (Received
16 October
1991)
Abstract er6onlc absorption and inA relation between an excess fluence of reorientational mode6 9 0 fluidEI on Bound modes In a number critical Bolutiom is a+scumed. 1. Hypmacouetic properties studied i~_Cll chow that in the _ proxiiuitg of crit-icalsolution point (T-!CC<3 K ) an exce6f3 a& sorption ha8 been observed in some binary solutions. Its value being essentially greater than the calculated contribution in absorption became of the interaction of ConcentratZon and
fit heat haa lution point Nitrobemzene/n-Dodecane) Ill and lower critic&I SolutiOn point aswellaaintheproximityofapecuMar (2 6 LutidIne/Mater oint of mlutiom iil. At the 8ame tim It appeared that not R all critical solution6 the hypersonic propagation ti been accompanied with the excem absorption rim near I=. Ror instance, in N+tmmethane/n--1 alcohol Cl1 and Nitmethane/ Zso-Oc-tane C3Y 8olutionf3 the hypersonic abmrptlon in the vicitity of I!, practically doem't depend on temperaturezklzE:*"W ~~~~o~~~f~~~=~b~~~~~~ tational modem of fluids on the souud wave. In NItmbenzene/ n-E&mane, Aniline/Cyclohexaue aud Nitrobeneene/n-l)odecane solutionl3 when Studying e~traof depolarizedRayle lum mattering some emilWrit "p6x1 in the behaviour of the?Peqolari-
m&dNewld!h have been obflervedC4,53. On the other hand thanMu-Amy1 alcohol and N-ltroethane/im-Cktane 8011~ tions t61 w V~BCOUB behavfcF of depolarized spectrum rridth ha6 been traced. !l!he reeult of temperature Invest tion of Rrillouin line width bu, (Le. of hypemonic abeorp 9aion) and depolarized lei,@ epectrm width El/ 2%~) (2 - relaxation time of re7 or entation) in NItrobeuzeneAl-Hexzme solution are premnted in f-0
I,,,
ceBB of molecule reorientat-lon in the dxrection of ient of acoustical wave velocity wa8 firat theoretical tie ly considered by Frenkel 171 and later 8imIlar ideas were put foxward by a mmiber of authors. Ih pmt-lcular,lt ham been shown ceB8 by acoustical C8,91 that the molecule reorientation wave 18 the remon of the appearance oTo additional ahear viscosity thu6 influencing on the cOniXlbUtifXL ValUe in acourrtical absorption caused by shear viscosity. ln the critical BolutIorus the shear viscosity nem To ha8 a weak anomaly which is in full agreement with dynamic ~cal-lrrg. Therefore W-2 additional shear viscosity resulting from the interaction of reorientation&l modeB with the acoustical modes +s rather amall and cannot account for either the behzxviour of Rrlllouin 1Ine width or Rayleigh depolarlasd B ectrum width. In these solutions the dependence of the inT eraction energy of unlike molecules on molecular reorientation Cl01 18 more ossible remon which determines the non-vticous dependence of s epolarized Bpectrum width.
8..
behavlour of de olariaed Raylei$h spectrum andJ3rllloulnlinewid & Oub in Nitmbenzene/n-Hexane 8OhItiOn. !b3 dashed 1iILemqIIW38ntS teUpratUre mOtiOn of hypersonic freq_uencyq .!l!heaolidlinea are guIdlrqg.
P
Temperature
% ihI wI
76
Thmmodynamic ~tab+litgofthe~~inthevic~tg of To may beconm the reason of enerw uuequality of all poa8ibreorientation fluctuation8, The latter in its turn may lead :: energy di~s~~t~on of sound_ field if _the v_aluerrqf sound __ rre encg arm the frequency of diesipation of anmotropy fluc8" tlla ion8 sxre clo8c3d. In fact our figure 8how8 the correlation between the te rature behaviour of reorientational fluctuations and the Br %- louin line width ma at tho8e temperature8 Wh0re the hypemonic frequency f'a approach.e8 to fre~ency of dissipation of reorimtational fluctuatiorm r . In EJitrobenzene/n-Dodecrme and Aniline/Cyclohex.ane 8olutiom3 the situation ia the 8me.
4. Generally 8'$zsAntg red reason of the apjmxrance of exe88 8ound ely to be typical for media where the dWectional bonds am famed between molecules. This refera especial1 to fluid8 with hydrogen bonds, B%oIn t%i 0 point Of View one 8hould pay attention t0 the correlation of data Concerning the sound ab80 tion and reorientation motion of molecule8 for glycerine, pub Tp ished inCll1 and 1121. m cl11 the 80und m80rpti0n at the frequency of 22 MHs at the te erature of about 273 K ha8 b&m observed. The temperature depe2 ence of average relaxation time of ycerine molecule reorientation a8 given by different author8. %k eented ln C121. It has been found that the 18-20 MHz aof dissi tion of reorientation fluctuations corremond8 z e re on op" the 273 K temperature. The frequency obaeked i? Fa % er Close to the Bound frmj,'u0~CyWhO8e absorption wa8 observed in C111. 1 2 3 4 5 6
L.Y.Sabirov, Ya.Turakulov. T,M.Utarova, J,Exp.Theor.Phy~. U!sSR), 79 (1980) 2263. s!.V.Krivokhidza. L.Y.Sabirov. Ya.Turakulov. T.M.Utarova, J.Erp.Theor. . Lett.Red. (USSR), 31 (1980) 746. ;;pbOS. PhEl G. ceF_. D.Bey6en8. Phy8.Rev.A.. 25 (1982) I.L.lkbelim3kii. V.S.Starlmov. A.K.Atakhodzaev, L.Y.Sabirov and T.M.Utarova, t.conm., 15 19E) 432. L.M.Kaahaeva, L.M. %!a birov. T.M. f tarova, I.A.Chaban, J.Exp. !l!heor.phyB.(USSR), 79 (1980) 1257. G.Zalczer, Ddteysens, J.Chem.Phya., 72 (1980) 348.
JOUrn& Of i%fOkCUilXF LigUidS, Fi4 (1992) 78-76 Elsevier Science Publishers B-V.. Amsterdam
lIArnIGH
LICEIT
sm
ING
spBI=TRB
IN
CRrrICAL
-
LM:.Ka6haeva, V.Yk.a.Lermm, L.M.Sabirov. T.M.Utarova and Ya.!Pmakulov Sanmrkmnd State Univemity, (Received
16 October
1991)
Abstract er6onlc absorption and inA relation between an excess fluence of reorientational mode6 9 0 fluidEI on Bound modes In a number critical Bolutiom is a+scumed. 1. Hypmacouetic properties studied i~_Cll chow that in the _ proxiiuitg of crit-icalsolution point (T-!CC<3 K ) an exce6f3 a& sorption ha8 been observed in some binary solutions. Its value being essentially greater than the calculated contribution in absorption became of the interaction of ConcentratZon and
fit heat haa lution point Nitrobemzene/n-Dodecane) Ill and lower critic&I SolutiOn point aswellaaintheproximityofapecuMar (2 6 LutidIne/Mater oint of mlutiom iil. At the 8ame tim It appeared that not R all critical solution6 the hypersonic propagation ti been accompanied with the excem absorption rim near I=. Ror instance, in N+tmmethane/n--1 alcohol Cl1 and Nitmethane/ Zso-Oc-tane C3Y 8olutionf3 the hypersonic abmrptlon in the vicitity of I!, practically doem't depend on temperaturezklzE:*"W ~~~~o~~~f~~~=~b~~~~~~ tational modem of fluids on the souud wave. In NItmbenzene/ n-E&mane, Aniline/Cyclohexaue aud Nitrobeneene/n-l)odecane solutionl3 when Studying e~traof depolarizedRayle lum mattering some emilWrit "p6x1 in the behaviour of the?Peqolari-
m&dNewld!h have been obflervedC4,53. On the other hand thanMu-Amy1 alcohol and N-ltroethane/im-Cktane 8011~ tions t61 w V~BCOUB behavfcF of depolarized spectrum rridth ha6 been traced. !l!he reeult of temperature Invest tion of Rrillouin line width bu, (Le. of hypemonic abeorp 9aion) and depolarized lei,@ epectrm width El/ 2%~) (2 - relaxation time of re7 or entation) in NItrobeuzeneAl-Hexzme solution are premnted in f-0
I,,,
ceBB of molecule reorientat-lon in the dxrection of ient of acoustical wave velocity wa8 firat theoretical tie ly considered by Frenkel 171 and later 8imIlar ideas were put foxward by a mmiber of authors. Ih pmt-lcular,lt ham been shown ceB8 by acoustical C8,91 that the molecule reorientation wave 18 the remon of the appearance oTo additional ahear viscosity thu6 influencing on the cOniXlbUtifXL ValUe in acourrtical absorption caused by shear viscosity. ln the critical BolutIorus the shear viscosity nem To ha8 a weak anomaly which is in full agreement with dynamic ~cal-lrrg. Therefore W-2 additional shear viscosity resulting from the interaction of reorientation&l modeB with the acoustical modes +s rather amall and cannot account for either the behzxviour of Rrlllouin 1Ine width or Rayleigh depolarlasd B ectrum width. In these solutions the dependence of the inT eraction energy of unlike molecules on molecular reorientation Cl01 18 more ossible remon which determines the non-vticous dependence of s epolarized Bpectrum width.
8..
behavlour of de olariaed Raylei$h spectrum andJ3rllloulnlinewid & Oub in Nitmbenzene/n-Hexane 8OhItiOn. !b3 dashed 1iILemqIIW38ntS teUpratUre mOtiOn of hypersonic freq_uencyq .!l!heaolidlinea are guIdlrqg.
P
Temperature
% ihI wI
76
Thmmodynamic ~tab+litgofthe~~inthevic~tg of To may beconm the reason of enerw uuequality of all poa8ibreorientation fluctuation8, The latter in its turn may lead :: energy di~s~~t~on of sound_ field if _the v_aluerrqf sound __ rre encg arm the frequency of diesipation of anmotropy fluc8" tlla ion8 sxre clo8c3d. In fact our figure 8how8 the correlation between the te rature behaviour of reorientational fluctuations and the Br %- louin line width ma at tho8e temperature8 Wh0re the hypemonic frequency f'a approach.e8 to fre~ency of dissipation of reorimtational fluctuatiorm r . In EJitrobenzene/n-Dodecrme and Aniline/Cyclohex.ane 8olutiom3 the situation ia the 8me.
4. Generally 8'$zsAntg red reason of the apjmxrance of exe88 8ound ely to be typical for media where the dWectional bonds am famed between molecules. This refera especial1 to fluid8 with hydrogen bonds, B%oIn t%i 0 point Of View one 8hould pay attention t0 the correlation of data Concerning the sound ab80 tion and reorientation motion of molecule8 for glycerine, pub Tp ished inCll1 and 1121. m cl11 the 80und m80rpti0n at the frequency of 22 MHs at the te erature of about 273 K ha8 b&m observed. The temperature depe2 ence of average relaxation time of ycerine molecule reorientation a8 given by different author8. %k eented ln C121. It has been found that the 18-20 MHz aof dissi tion of reorientation fluctuations corremond8 z e re on op" the 273 K temperature. The frequency obaeked i? Fa % er Close to the Bound frmj,'u0~CyWhO8e absorption wa8 observed in C111. 1 2 3 4 5 6
L.Y.Sabirov, Ya.Turakulov. T,M.Utarova, J,Exp.Theor.Phy~. U!sSR), 79 (1980) 2263. s!.V.Krivokhidza. L.Y.Sabirov. Ya.Turakulov. T.M.Utarova, J.Erp.Theor. . Lett.Red. (USSR), 31 (1980) 746. ;;pbOS. PhEl G. ceF_. D.Bey6en8. Phy8.Rev.A.. 25 (1982) I.L.lkbelim3kii. V.S.Starlmov. A.K.Atakhodzaev, L.Y.Sabirov and T.M.Utarova, t.conm., 15 19E) 432. L.M.Kaahaeva, L.M. %!a birov. T.M. f tarova, I.A.Chaban, J.Exp. !l!heor.phyB.(USSR), 79 (1980) 1257. G.Zalczer, Ddteysens, J.Chem.Phya., 72 (1980) 348.