SCIENTIFIC ABSTRACT PEKAR, S. I. - PEKAREK, L.

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• Collection: Scientific Abstracts
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• Publication Date: December 31, 1967
• Content Type: SCIENTIFIC ABSTRACT

SOV/56-37-2-27/56
Light Waves in Crystals in the Range of Exciton Absorption and the Impurity
Photoeffect
An estimate is also made of the relative magnitude of the waves
generated in the crystal. The amplitudes of the two transverse
waves are considerably smaller than the amplitude of the '-n-
cident wave. The amplitudes of the longitudinal wave is of
the same order as the incident wave if the incident angle
is not too small. It appear3 that the longitudinal wave is
very intensive, dominating the transverse wave. B) 1~1 this
case co-col holds, the refractive index of the normal trans-
0
verse wave being much smaller than unity. The amplitude of
one of the transverse waves becomes negligibly small, and
all properties of the (normal) transverse wave approximato
those following from the conventional electromagnetic optics
of crystals. The relative magnitude of the amplitudes of the
waves occurring in the crystal are estimated. If Inj , sin y
holds, the amplitude of the longitudinal wave is of the same
order as that of the transverse wave Inve8tigated above, This
means that it may be several hundred times that of the incident
wave. If I n I < sin (p the amplitude of the longitudinal iwave
is in excess of that of the normal transverse wave. In a diagram
Card 2/4 the frequency dependence I EII/A P1 is shown. These approximations

30V/56-37-2-27/56
Light WoLves in Crystals in the Range of Exciton Absorption and the Impurity
Photoeffect
are true only for an absorption sufficiently weak so as to
justify a neglect of the imaginary part of n2. In the integrals
used herein, however, even a small.imaginary part of n2 is
essential. In case A, where the ampli-tudea of the four trans-
verse waves are of the same order,,.the results found in this
study differ from ordinary cryetal optics. In case B the normal
transverse wave has almost the same properties.as in ordinary
crystal optics. The energy flux entering.the crystal, which
diffen from zero, and which is connected with the energy
expended in photoionization, may be aetermined in the follow-
ing approximation, if the weak absorption in.the crystal is
taken into account. In the following part the case of the re-
fractive index being equal for two waves with identical polari-
zation is discussed. The two pertinent linear independent
solutions are written down. Both solutions represent waves
with a zero group velocity. In the third section the frequency
dependence of the impurity photoeffect in the range of ex-
citon absorption is discussed. The authors express their
Card 3/4 gratitude to I. G. Zaslavokaya for carrying out the numerical

SOV/56-37-2-27/56
Light Waves in Cryutals in the 114nge of Rxciton Absorption and the Impurity
Photoeffect
calculations. There are 6 figures and 11 references, 6 of
which are Soviet.
ASSOCIATION: Institut fiziki Akademii nauk Ukrainakoy SSR
(Institute of Physics of the Academy of Sciences of the
Ukrainskaya SSR)
SUBMITTED: March 10, 1959
Card 4/4

S/181/60/002/02/12/033
B006/BO67
AUTBORSt Pekar,-S.-- I-., Tsakvava, B. Ye.
TITLEt Light DispersionNin the Range of Exoiton Absorption in Cubic
Crystals With Regard to the Anisotropy of the Effective
Exciton Mass
PERIODICALt Fizika tverdogo tela, 1960, Vol. 2, No. 2, pp. 261-272
TEXT: The present Daper is a continuation of previous papers (Refs. 1-3)
in which the theory of dispersion and exciton absorption of light was
dealt with. The present paper differs from the previous papers in that
the anisotropy of the effective exciton mass in the cubic crystals is
taken into account. In the present paper, the investigation is made
generally without special assumptions on the Hamiltonian of the system
and without restriction to a certain exciton model. The properties of
the exciton energy bands which are determined from the cubic symmetry
of a crystal of class Oh, are analyzed by group-theoretical methads.
Since light interacts only with the excitons whose wave vectors k coincide
with those of light, only the following cases are examineds ek) q parallel
Card 1/3

Light Dispersion in the Range of Exciton B/181/60/002/02/12/033
Absorption in Cubic Crystals With Regard to the B0061BO67
Anisotropy of the Effective Exciton Mass
to the edge of the basic cube (direction (0,0,1))~Jb) -kIis 5arallel to
direction ("I"); a) ~ is parallel to direction ,I,0); d It is in the
face plane of the basic cube or in the bisectorial plane of an angle
formed by the intersection of two faces of the cube (see Tables 1-4). In
the followingp the paper deals with the selection rules and the
polarization in phototransitions of the crystal from the ground state
into the exciton state. Furthermore, the dispersion of normal and anomalous
light waves is calculated by taking account of the anisotropy of the
eff-octive exciton mass, and an expression for the refractive index is
givan. The results are applied to the theory of electromagnetic waves
in media with exciton absorption which iras developed in Refs. 1-3. In
conclusion, the possibility is discussed of proving birefringence in
cubic crystals experimentally. These experiments must be conducted at
extremely low temperatures. The authors thank E. I. Rashba for remarks.
Ya. I. Frenkell and K. B. Tolpygo are mentioned. There are 4 figures,
6 tables, and 15 referenceat 8 Soviet, 4 American, 2 German, 2 British,
and I Dutch.
Card 2/3

FAXAR, 3-1.; STHUMTSKIT, V-0-
Theory of the effect of tesperature on the dispersion and *)d ton
absorption of light In crystals& Yise tvar. tela 2 noo5s894-897
W 16o. (HIPA 13:10)
1. Kiyevskly gosudarstvenVy universitat.
(Crystal Optics)

25582
S/185/60/005/002/019/022
(11"1137 rjlvs~~ D274/D304
AUTHORS: Pekar, S.I. and Stryzhevs'kyy, V.L.
TITLE: On the theory of temperature dependence of disper-
sion and exciton absorption of light in crystals
PERIODICAL: Ukrayinalkyy fizychnyy zhurnal, v. 5, no. 2, 1960,
277-279
TEXT: In previous works by S.I. Pekar the temperature T of the
crystal was considered as nearly zero. The present article is an
extension of the theory to temperatures different from zero, at the
expense of certain limitations on the type of Hamiltonian. The me
hod of calculation is similar to that of S.I. Pekar (Ref. 3: ZhETF
369 4510 1959) with additional limitations. It is assumed that in,
the zeroth approximation the crystal is composed of two subsystems,
that the interaction energy is a first-order qua~gt ity, and that the
excitation energy of the first subsystem is much reater than kT.
The subsystems are distinguished by the fact that light can lead
to phototransitions in the first subsystem only, creating excitons.
Card l/ 3

S/185J60/005/002/019/022
On the theory of teniperature.60 D274/D304
The polarization of
cit). The term (in
meter 'Y . given bv
the crystal is given by formulas of Ref. 3 (Op.
these formulas) for absorption, contains a para-
21r 12 (2)
DpOO) I Umq a q
p
which is responsible for the temperature dependence of the disper-
aion m is the index for the wave state, q is the
index for the whole system into which the exciton may pass under
the effect of the interaction U, iEq is the energy of the system in
a state corresponding to olae of the quantum numbers, p is the total-
ity of the other quantum numbers of the same state, and P is the
number of states. In order to obtain the temperature depeRdence
explicitly, it is necessary to specify the interaction U. After
some transformations, and expanding U in powers of q an expression
is obtained which leads to
(11 +1) + f, (e
increases with V. n the limit for high temperatures, I is pro-
portional to T. If the frequency dispersion can be ignored (for
Oard 2/3

BRODIN, M.S.; MIMI, S.I.
Experimental proof of the existence of anomalous additional IiEht
waves in crystals in the exciton absorption region. Zhur. eksp. i
teor. fiz. 38 no.1:74-81 Jan 160. (MIRA 14:9)
1. Institut fiziki Akademli nauk Ukrainskoy SSR.
(Anthracene crystals) (Excitons) (Light)

81671
S/036/60/038/06/06/012
BOO6/BO56
AUTHOR: Ptkar, S. I.
%
TITLE-. Identification of Excitons' With Light Waves in a Crystal
and the Macroscopic Theory of Eicitons With and Without
Consideration of Retardation
PERIODICAL: Zhurnal eksperimentallnoy i teoretich08koy fiziki, 1960,
Vol- 38, No. 6, pp. 1786 - 1797
TEXT: In the introduction the author discusses the methods and the results
obtained by such investigations carried out in earlier papers of his own
as well as in other publications, and gives a detailed description of the
two possible methods of investigating excitons in consideration of retar-
dation. The first method was used by the author in his earlier papers
(Refs. 2, 4, 7) and the latter method was uned in this case. It consists
in the following: A macroscopic electric field accompanied by a light
exciton wave is described by the Maxwell equations. If this field is con-
sidered to be a light wave, and if the wavelength is assumed to be small as
against the lattice conatant, the field may be treated with the usual
VK
Card 113

81671
Identification of Excitons With Light Waves S/056/60/038/06/06/012
in a Crystal and the Macroscopic Theory of B006/BO56
Excitons With and Without Consideration of
Retardation
macroscopic crystal optics. The retardation may be considered in long-
range interaction. From the formula ug = ke.) k the light exciton energy
-4
may be calculated. W = Lz(k) and 6 = e (w, 6; various properties of the
light excitons may be described by the latter tonsor. First, the various
types of light exciton possible in a crystal are described, and expressions
for the boundaries of the exciton energy bands, their energy limits for
k--.,'-0 etc. art given in terms of the tensor of th* dielectric constants The
following three possibilities are dealt with: 1) The longitudinal light
_~P _* I" --b.
exciton ENS, 2) The transverse light exciton E-La. 3) That light exciton
in which 9 and -8'* form an angle that is not a. right angle. In the following
expressions are obtained for the effective masses of these excitons. The
results obtained for c-.,,oo go over into those of the ordinary exciton
theory, where the retardation of the interaction between crystal particles
is not taken into account, and which is based upon the Schroedinger equa-
tion.A zomparison between the results obtained shows that, if the wave
Card 2/3

81671
Identification of Excitons With Light Waves s/o56/6q/038/o6/o6/012
in a Crystal and the Macroscopic Theory of B006/BO.56
Excitona With and Without Consideration of
Retardation
accompanying the exciton is longitudinal (Ella), the retardation may be
negliocted. If, on the, other hand, the accompanying wave hai5 a rotation-
al field, consideration of the retardation influences the rosulta quite
esseitially if those regions are taken into account in which the re-
fractive index is not. very great-, this consideration leads to consider-
able values of the energy and the effective mass of the ex(:itons, which
deviate from those obtained by proceeding from the Schroedinger equation.
The author finally thanks L. D. Landau, who is the initiator of this
investigation, as well as E. 1. Rashba and M. A. Krivoglaz for discuss-
ions. Also Ya. 1, Frenkell is mentioned. There are 1 figure and 13
references: 10 Soviet and 3 American.
ASSG",IATION.- Institut fiziki Akademii nauk Ukrainakoy SSR (Institute
of Physics of the Academy of Sciences of the Ukrainskay
SUBMITTED: January 2, 1960
VK
Card 3/3

85701
S/056/60/036/006/044/G49/,Y7,
B006/B07O
AUTHORS: Brod2n, hi, S , Pekar S.. I.
TITLE: Additlcnal Anomalous Lighl. WavP-s in AnthTacene ir. the Rewi~n
of ExciTon Absorption 0
PERIODICAL: Zhurral Pkeperitrientallnoy i teoreticheskoy fl2iki, !960
Vol, 38. No. 6, pp~ 1910 19112
TEXT: The existence of add:tional anomalous light waves in crys*q-1," n
the region of eyc--tor absorrpt,.on was theoretically predicted by Pekar
(Refs 1-3). An ;,xper-imental proof of thi(i assumpti,n was quggest,~'d by
the present authors in Ref.4. In the s&m,~ paper a1sD data of Previois
measurements of light absorption in anthracene plates of differert. th.:k
ne8B had been 9valuated (in the region of ~harfict-7risti- abs:)rpl~iDr..
maximum at. 25 200 cm P. was found that ',hA int(insity of
light as a function of the plate thickness was subjoct to flu,7t.1,at,irr,5
In the present, "Letter t,) the Editor". a report is made on th,~ absol,t-
measurement of the intensity of light by th~- method of photcgraphi,
Card 1/3

85701
Additional Anomalous Light Waves in S/05 6 c/o 3 a /006/044/,-.4 ~/U
Anthracene in the Region of Exciton B006YB070
Absorption
photometry (refer-3ncA line: 24 720 m A s~e-trogra-,h th-
06-~' (DFS-3) was used fcr 30 differi-n-. .ni~.kri-sses cf the --rvstal T"
measured optical dens,,.ty of the -rysta! as a function o.' its th;,~knr-.sa
"08 'M 1
for the frequency 25, is shown in a diagram (T - 2C K) Thp -s
cillation charactar is here clearer than in the curves of Ref.4. It, .5
noted that the separa-.ions 61 of the extrEoma are about equal (abscissas
of the maxima. I - -0,072. 0.1.26 0.188, 0.245 ~Li
separations: ZAI -0.0"-
0.060, 0.057 p; minima; I ~ 0.'05, 0.'68. 0.233 o; separation-,.
61 - 0.063 and 0.055 4), With this '. the P-erage perod of os~illat:-n iF
found to be 0.058 P, and the -:,rrespondng differen-,e in "he refrac~.:--P,
indices of two in!-erferirg waves to be 6.9. The character of 1%~e
shown in the Fig, is -.hat of a th~orp~.ical 7urve des,-ribing 1.h~ -,nt-r
ference between two parall-I anc~malous waves polarized :n parallel T~.~-~
more accurale measurements again demons'~rate 1~he ---xisten.-e of add---n,,,
anomalous waves in the crystal of anthracene as is required by the
theory. A. F Prikhot,ko is thanked for interest and discuss:.ons. and
S. V, Marisova for heap in experiments. 1, V. Obrei,-::,~ .a ment,oni~d
Card 2/3

Additional Anomalous Light Waves in S/056/60/038/0061.
Anthra,7ene in the Region of Exciton Boo6/BO70
Absorption
There are I figure and 6 Soviet references.
ASSOCIATION: Inatitut Fiziki Akademii nauk Ukrainskoy SSR (Institute of
Physics of the Academy of Sciences Ukrainskaya SSR)
SUBMITIED: March 19, 1959
Fig.

Fig.

tj -

card 3/3
It
Vs V

3/181/62/004/005/0,54/055
B106/B112
AUTHORt Fekar S 1.
TITLN'i On tho theory of additional olootromagnotio wavon in aryotalo
in the ranCo of exciton aboorption
P'1;113IO'A)ICAL: Fizika tverdogo tela, v. 4, no. 5, 1962, 1301 - 1~il
TEXT: This is a review of results deduced by the author from the above
mentioned theory in earlier papers and of its consistence with experiments.
Particular attention i3 Daid to the problem of the additional boundary
conditiolp at the crystal surface that are necessary for determining the
amplitudes of the waves in the crystal by means of the amplitudes of the
waves incident from the vacuum. It is shown that the boundary conditions
proposed by V. L. Ginsburg (ZhSTF, 34, 1593, 1958) are not applicable.
Light is throrm upon the question why it is necessary to use a quantum
mechanical d,,scription of the motion of the particles in order to determine
the spatial dispersion of the dielectric constant. The approach by way of
expanding the inverse dielectric constant into powers-of the wa*7e vector
(V. L. Ginzburg) leads to results that contradict the quantum machanical
Card 1/2

j I
S/05 62/04 3 100 3/0;5.j/~ 6
B104Y2102
AU MORS: Pokar, S. I. Perlin-, Yu. 1e.
T-L T'- The of excited F centers
P': R I ODI CA,-,: Zhurnal eksperimentallnoy i teoreticheskoy fiziki, v.
no. ;~(9), 1962, 1108-1110
r
TEXT: Calculated 4nd exprimental results for the radiation lifetimja
of cited F cente s are shown to be in good agreement, the forz-r
tas% -- F centers of ionic crystals establ.
d on tne contituou~ theory ol
b~ S. 1. Pekar (1---sledovaniya po elektronnoy teorii kristallov
into th& el~~ctron theory of cryst,is, Gcst-Ahizdat, 1951; ZhETF,
19'2) and the latter obtained by R. K. Swank and F. C. Brown (Ph'-s. R,-'~-.
,ett., In, 1c), 1962). Th,,, formula
1 = 4e 2nQ 3z2 / 3 t~ C.5
R m 21
i f; ('Iediced for tie radi r-,tion lif etime. QL is the maximum fre~,,Uerc~ 1.
IL m
;uminest-ence band,,n is the refractive index. Results:
ard 1/2
C

q -7 C)
AUTHOR: Pekar, S. I.
S/053/'62/077/002/005/004
B117/B138
TITLE - Additional light waves in crystals and exciton abnor-,)tion
H!,iIODICAL: Uspelchi fizi;,,heskikh nauk, v. 77, no. 2, 1962, 309 - 319
TEXT: This paper was read at the plenary meeting of the VIII
Soveshchaniye po fizike nizkikh temperatur (8th Conference on the Physics
of Low Temperatures) hel'd in Kiyev on October 13, 1961. It deals with
71estern and Soviet papers published since 1957 on progress made in the
inveEtiGation of additional light waves in the range of theexciton absorp-
tion band. The existence of such waves, as well as-the known waves of
birefringence, werepredieted by the authcr (ZhETF 33, 1022 (1957)). It
was Shown that two light waves may exist in a crystal, which have the same
polarization and pnpagate in the same direction but at different veloci-
ties. Theses waves were found to exist only near exciton absorption bands.
An e3oa~iton with life long enough for. heat transfer is an excitatJ.on' of the
crystal with a single continuous quantum number (quaai-momentum 'R ).
Since the life(path length)of the exditon increases with decreasing temper-
Card 1/2

S.I.- SUWO1', V.I. (Subakovp V.I.]
Ob supplementary boundary conditions in the theory of add.Ltional
electromagnetic waves in crystals. Ukr,fiz,zhur. 7 no.1liill9l-
U94 N 062, (MYRA 15:12)
1. Kiyevskiy gosudarstvemyy universitat im. Shevchenko.
(Boundary value problems) Mectrmagnetiv vaveo)
(Cry-atalv)

FIUSHV S.E.,, otv. reA.; BOWVICH, Ya.S., kand. fiz.-matem. nauk, red.;
VOLIKENSHTEYN, M.V.,, doktor fiz.--matem. nauk, red.: GALAIIIN,
M.D., doktor fiz.-matem. nauk, red.; DIIUJKAREV, G.F., doktor
f12.-matem. nauk, red.; YELIYASHEVICH, M.A., akademile, red.;
KALITEYEVSKIY, N.I., doktor fiz.-matem. nauk, red.; IWSAEOV,
H.M., doktor kbin. nauk, red.; LIPIS, L,V., doktor tekhn.nauk,
red.; doktor fiz.-maten. nauk, red.; PFd)KOFIYEV,
VA., doktor fiz.-matem. nauk, red.; SOKOLOV, N.D., doktor
fiz.-matem. nauk., red.; MFILOV, P.P., doktor fiz.-Yoatem.
nauk., red.; CHULANOVSKIY, V.M., doktor fiz.-matem. nauk, red.;
SHPOLISKIY, E.V., doktor fiz.-mqtem. nauk, red.; YARC)SLAVSKIY,
N.G.., kand. f12.-matem. nauk, red.; LEKSINA, I.Ye., red. izd-
va; PENKINA, N.V., red. izd-va; NbVICIEKOVA, N.D., tel:hn. red.;
KASHINA, P.S., tekbin. red.
(Physical problems in spectroscopy]Fizicheskie problemy spektro-
skopii; materialy. Moskva, Izd-vo Akad. nauk SSSR. Vol.l. 1962.
474 p - (W RA 16:2)
1. Soveshchaniye po, spektro8kopti. 13th, Lmingrad, 1960. 2. Claen-
korrespondent Akademil nauk SSSR (for Frish). 3. Akademiya nauk
Belurusskoy SSR (for Yellyashevich).
(Spectrum analysis)

VEMSELI, G.F.; PEKAR, S.I.
-.- -------
Surface exciton energy at extremely amall. quasi-moioenta. Fiz.
tvar. tela 6 no-3:811-817 Mr 164. Ooff RA 17:4)
1. Institut poltiprovodnikov AN UkrSSR, Kiyov.

441ho
8/101/62/004/0'10/0127/063
B100104
AUTHORS: Kventsel', G. F., and Pekar, S. I.
TITLE: Conaideration of' the surface excitons in the theory of
electromagnetic waves in crystals
P'ZRIODICAL: Fizika tverdogo tela, v. 4, no. 10,.1962, 281B-2828
TEXT: To gain insight into the role of surface excitons in crystal optics,
the cuthora calculated the polarization current arising in a crystal under
the &ction of the electric field of a lifht wave. The Maxwell equaiAt4na are
solved for that part of the polarization current which is due to surface
excitone in a bounded crystal:
rot rot f'2 if
TS C2
E.e- E.1-0;
a ;, (12),
[q.[q., 19..L E.,
(w, qg)E.=Bm ------- T- (17)
got qNs I-
qN, 9:r
Card 1/3

Consid.eration of t~,e surface.,.. B198YB104
E, E, (q,, Ej; E. E. - (q., E.),
q!
B('
.,y CS hw - 46. FW_;7_46. (0)). (19).
~~03 13 that part of the polarization current as'sociated with virtual
transitions into surface exciton states. q is the quasimomentum, S is the
area of the region in which the wave functions of the surface excitons are
Y> r 0 lihion> , i(r-) is the operator of the polarization
orthonormal. on ("') - < -q-
current density. ThU3, in a non-absorbing crystal appear undamped waves
and waves damped in the volume of the crystal and associated with the
surface excitons. The Fresnel formulas are extended to the boundary
between the crystal and the vacuum. They can appear in a considerably
different form when a surface exciton exists. In a non-absorbing
isotropic medium, for instance, the reflected atid'tranamitted waves are
elliptically polarized. There is 1 figure.
S/18 62/004/010/027/063
Card 213

8/18 62/004/010/027/063
Consideration of the surface... BlOeXB104
ASSOCIATION: Kiyevpkiy gosudaretvennyy universitet im. T. G. Shevchenko
(Kiyev State University imeni T. G. Shevchenko)
SUBMITT30: May 28, 1962
Card 3/3

(Ito
44094
S/185/62/007/011/006/019
D234/U308
G
AUTHORS: Pekar, S.I. and Su�alcov, V.Y.
TITLE: idditional boundary conditions in the theory of
additional electromagnetic waves in crystals
PERIOOIC;~L: Ukrayinslicyy fizychnyy zhurnal, v. 7, no. 11, 1962,
1191-1193
TZXT: The authors refer to 4 previous papers by S.I. I)ekar
(Zh-":'TF, 33, 1022, 1957; 36, 451, 1959; 34, 1176, 1958; FTT, 4, no. 9L,'
1962) where the existence of additional waves was established and
additional boundary conditions were found,. taking into account the
dipole-dipole short-range interactions-of elementary cells only.
In this paper, longr-range interactions are taken into account, con-
sidering a semi-infinite anisotropic crystal with an arbitrary sym-
metry. The wave function is represented as a sum E Cnc( (DIVXI
which is substituted into Schrodinger's equation. The! resulting
equation is satisfied if
(Cn,x) n3-0 - 0 (8)
Card 1/2 'J As ~j q_-, I- j n0jJ LD ~!, ~C. S

5/185/62/007/011/006/019
Additional boundary conditions ... L)234/D308
assuming that (I',. ai) e-< I and replacing the sum (8) fAbstracter's
note: This equation 2robably contains a misprint2 by an integral,
which is interpreted as the interaction energy of a dipole in the
nth cell and a semi-infinite polarized continuum. The contribution
if virtual transitions into the exciton state to the po,arized
dipole moment is equal to zero on the surface of the crystal.
ASSOC IATION: Kyyivs'lcyy derzhut-Liversytet im. T.H. Shevchanka
(Idev State University im, T.H. Shevchenlto)
SUBI-111TICE"D. I-lay 12, 1962
Card 2/2

FIMAR, S.I.
Theory of additionp-I electromagnetic vaveB in the exciton
absorpticku region In crystalr.. Fiz. tvcr. tela 1, no.5-,1301-133-1
liq a 62. (MIRA 15: 5 '1,
1. IrLsti-tut poluprovodnikov AN USSR, Kiyev.
(Electromapetic waves)
(Zxcitom) (Crystal lattices)

7EREZHEPOVI M.Ye.;_PE~
Theory of the electroconductivity of semiconductors allowing
for fAelds of charged impurity centers. Fiz.tver.tela 5
no.5tl297-1303 My 163. (MIRA 16t6)
1. Kiyevskiy gosudarstvennyy universitet imeni. T.G.Sheivebenko.
(Semiconductors-Electric properties)

KVEIVTSELI, G.F.; FEKIR, S.I.
aking allowance for surface excitons in the theor7 of
ectroragnetic waves in crystals. Fiz.tver.tela 4 no.lOt2818-
A28 0 162. (MIRA 15:12)
1. Kiyevskiy gosudaretvennyy universitet imeni T.G.Shevchenko.
(Exciton;q) (Electromagnetic waves) (CryBtal optics)

DEMIDITKO, A.A.; I'MAR, S. I.
Raflection and transmistjion coefficients for a plane crvs-.a'L
surface in the region of exciton absorption of light. Fiz.
tver. tels, 6 no.9:2771-;'779 S 164.
(MIRA 17:11)
1. Institut poluprovodnikov Ali UkrSSR, Kiyev.

fT.
7t'EJ'CrV Of
no.

ACC NRI AF70D.3220 SOURCE CODEs W66A166165V6D61i8iiA82o_'
..AUTHOR: Mallnevp V. W.; PeMr. S. 1.
ORG: Kiev State University (Kiyevskiy gosudarstvewwy universitet)
TITLE: Intermolecular Interaction and the equation ;of state of a high.4 excited gas
SOURCE: Zh eksper i teor fi;,.p v. 51j, no. 6. lWo *3.1-1820
TOPIC TAGS: molecular interaction,, excited state, equation of state,, dipole in'ter-
action., Van der Waals force.. ideal gas, laser r andd
ABSTRACT: The authors consider a gas with sufficiently high molecule concentration
(such as at atmospheric pressure), when the average distance between molecules is
much shorter than the wavelength of the light absorbed by these molecules. Unlike ini
earlier investigations) the case is considered when a large percentage of the mole-
cules is excited to the same electron energy levels.' It is shown that the dipol
dipole interaction of two identical molecules situated at different energy levels
inversely proportional to the cube of the distance and does not vaninh upon averaging~
over all ponsible orientations of the molecular dipoles. This interaction makes an
appreciable contribution to thermodynamic functions and the equation of state of the
excited gas and can exceed the ordinary Van der Waals force and lead to deviation of
the gas frota ideal behavior at pressures that are not very large, and to its conden-
sation. Calculations are made for the case of monotonic molecules and it is shown
that such a highly excited gas bas several anomalaus features, nameXy an anomalously
Card 2/2

L EWA(h)/EK(I)/'r 1JP(Q AT
ACC Ngs AP6012471 B0=3 CODB; MV0183/06/005/"*/114/n0_l
4UTHOM. Mar 1.
Xiev State University im, T* 0, Shevcb!!!~o (Myev&My gosudar tvenrWy universi-
OBG:
tet)
7STLE.i- Theory of,.m?bil1ty., Hall-effict* ana.magnetoresistance In electronic semi-
ly?conauctors vith charged aefects
SOME: Mika tverdqgo tcla., v 8., no. 4.,~ 1966., M5-na
.TOPIC TAM: semiconductor airwle crystak, electron mobilityp Hall effect,, magneto-
resistM MY481 defect.* electric conductivityp semiconductor bancl structure
ABSTRACT: The author calcu.1ates theoretically the chuge In mobility., the Hall con-
stunt.. and the magnetoresistance., due to spatial bibow9enelty of the semioDnductor
as the result of the defect fields. The effective radius of the defect fIe3A Is
assumed to be of the order of the DelTe screening radius and considerably larger than
the carrier mean free path; the carriers move in diffuse manner in the field of the
defectso The field of the defects is introduced into the equation fD.- electric con-
ductivity and for diffusion and is treated macroscopically on par vith the external
amplied field. -Account is taken of the redistribution of the carrier density due to
the. defect fields and of the spa#al3y inhomogenemis currento Tbe microscopic cur-
rent denBity averaged bver tbe crystal crOB19 section to calculated wLth accurscy, to
first-degreeterms in the ajWlied electric field and termo of arbitruT power in the
~d 312
_Q
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L 26502-66 EWT(I)A (M)/T~~Wp(t) IJP(C) GG/31)
ACC NR3 Ala,12472 SOME CORE: WO19V6q0_W/OD4/l=/11
J
AUTROM Xbiwshiny Yu. Ve; 0. 1. ~B
ORD: !Ydev FUte UnIvers im. T* 0. Sbev&en~pjXiymaklygosudarotvewjVuniversitet;
_.-IME: Thepry of mobility, 3all effeetp and magnetoresistance in semiconductors with
t' linear. dis3j~c IM
`;~tDURM ika t1veAdogd telay v. 8,, no 4#,2W# 31W-lW8
TOPIC, TAGS.-: sUctron mobilityp ,FJA.U effeetp magnetorexistance.. samicouftetor single
taly crystal dislocation phenomenon, transport theoryp carrier density
ABSTRACT: This,is a companion to a paper by one of the authors in the same source
.(Pekar.. p. .1115., Ace. AF6o:L247i inalth e eral theory developed An that paper for
the influence L Of - qMstal defec&n ~,ran_ __ _ _ pbcninena is applied to the case when
the defects are Unear dielcications. Account Is taken of the Influence of the de-
formation and electrostatic patential of the charged dislocations. lbe mobilityp
stance., and the MU. effect are calculated for a cubic crystal or for an
isotrapic viedium with isotropie and anisotropic distribution of the Uslocations with
respect, to the ftrections. Ualike earlier papers dealing with this subject.. the case
-is considered when the Debye screenizg radius of the dislocation field is much larger
than the mimn free path of ibe carrieTes due to scattering by thermal lattice vibra-
tions and other tactors. is sliom that allomize for the deformation potential
'Locations introdmes only tmall corrections
-of the die., to the transpoit theory; these
V0

lv,K4A) S.I.
Electror"F~onom intEtractLcn, I to an
applied field, ard the anplificalLl-)n of --ound In semi,:~G.-,ftictors.
Zhur. eksp. i tzor. fiz. 49 Ag 165. (AURA 18:9)
1. Institlit. pc.1-ujxcvudni1.crj AN Ulx~JSY)

L 01218-66: EWA(h)/1~qjl)/T IJP(cl.. AT
AMMOR: Pokar, S. 1.
TITLE: Electron-phonon Interaction, proportional Co the extelrnal applied field
and sound asqilification in semi conductors
Y,
SOURCE, 2hurnal eksperimentallnoy I teoreticheskDy fiziki, v. 49, no. 2, 1965,
-629
6
21
TOPIC TAGS: electron phon0n interaction, hypersound, dielectric pe:meability,
deformati( in, piezoelectricity, phonon
ABSTRACT: The mechanism of electron-pbonon interaction associated vith the
dependencei of dielectric permeability of the cr7stal on deformationa has been
investigated, It was established that when an electric field is applied, such a
neckinnismoperates In piezoelectric a3 well as in non-piezoelectric crystals. The'
stud.V led to the identification of four types of vaves occurring in isotropic
semiconductors. Three'of these waves can be amplified by-the field.: 1) a vave
perpendicular to the direct-ion of carrier propagation; 2) a longitudinal wave; ands
3) a drift wave accompanied by shifts In the medl=6 A second traniiverse wave is
not affected by electron-pbonon interaction. It to shown that the Investigated
phenomenon can cause, in substances with an anonalbus high dielectric permeabilityi
cwa 1/2

3.6284-
'UrKWUM
AP4045726
/6,006/00311).'6615/6625
AMIHORt 'Pokar, S. I.; ~?erllpj li, Y~.
s- Lot'z-lrumlin c'entfirs, in iorlo c-rZatalp
T
SO 01ca statui- oll dl v 6 no. 3, 1964t 615-625
TOPIC TAGS1 j enter, enorKy levelp 2a atatep 2p state, F-luminegeence, local
electron ctinter, emission %mbabilityp-aimorption probability
AB STRAGT-z~ This pa or anal;yzes.the statements by W. Beall Fowler ard D. L. Dext
P or
(PhYs. Stat. sol. 2t 8231 1952; 31 1865p 1962) about the-F--,center theory, It is
shown that# in spito of Stokes shift' and diff orenve in the Frank-Condon matrix
-,~Olsments,or absorption andemission transitions$ Einstein's relation for expressing
t
he-e~desion probability in terms of light absorption probability ceLn be employed
without- li-mitations or. appmimations. Formulas ime derived for,tho integral 3-n-
to ity: of: ikp=xty- aboor-ption and emission. Tho'good agreement betwoon many theo-
one
retUal, ard e"~erimental-risultsj o4enin the caso of alkall-halide~cryatalsj whan
th ele -ion 6Tbit rad,'Lus i-doos iiot exceed, the I' ant a ~'r,